JPH0754091B2 - Internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an internal combustion engine such as a diesel engine.

[Conventional technology]

Conventionally, in a diesel engine, which is a type of internal combustion engine, a direct injection method that directly injects fuel into a single main combustion chamber for combustion and a sub combustion chamber in addition to the main combustion chamber are provided as combustion methods. A fuel injection nozzle having an injection port opened on the inner wall of the sub-combustion chamber, the fuel injection nozzle being provided in the cylinder head following the injection port to inject fuel into the sub-combustion chamber through the injection port for temporary combustion. There is a sub-combustion chamber system. In particular, with the recent trend toward miniaturization and higher speed, it is necessary to complete combustion in a shorter time, and therefore, a high speed combustion is possible and a sub-combustion chamber type that is low in noise is widely used.

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

The hot plug installed in this way is equipped with a turbocharger as the diesel engine becomes smaller and faster, and is composed of high-grade heat-resistant alloys such as nickel and cobalt in terms of heat resistance and heat insulation. However, there is a problem of poor durability.

In addition, since the sub-combustion chamber is made of metal, it has good thermal conductivity. Therefore, the heat of the hot plug is conducted to the cylinder head cooled by the cooling water. The combustion gas is cooled by the wall surface, the warm-up characteristics at the initial stage of engine start are extremely deteriorated, and misfires easily occur.As a result, HC and other gases are generated, and combustion in the main combustion chamber is inappropriate. However, there is a problem that smoke is generated, and there is also a drawback that the auxiliary combustion chamber made of a heat resistant alloy such as nickel or cobalt is extremely expensive.

Therefore, as the heat load increases due to higher performance as described above,
By constructing the auxiliary combustion chamber, which has the highest temperature, with an inexpensive ceramic material such as silicon nitride, sialon, carbon silicon, zirconia, and ricia, which has high heat resistance and excellent heat insulation, the heat insulation and heat retention of the ceramic material As a result, the cooling water loss is reduced, the atomization of injection combustion in the auxiliary combustion chamber is promoted, the ignition delay of the air-fuel mixture is reduced, and its combustion is improved, and the amount of particulate emissions in exhaust gas is reduced. There is a proposal to do so.

Further, in order to improve the startability and the stability of combustion at low speed, a heating element is arranged in a part or the whole of the auxiliary combustion chamber to control combustion, and in order to further improve the combustion state, the auxiliary It has also been proposed to support a three-way catalyst on the inner surface of the combustion chamber to reduce the amount of harmful substances such as HC, CO and NOx generated.

[Problems to be solved by the invention]

However, if the auxiliary combustion chamber is made of ceramic material, many attempts have been made to improve the cross-sectional shape of the injection holes in order to improve the combustion and to improve the heat insulation effect of the ceramic material. It was difficult to improve the combustion over the entire combustion region in the complicated combustion situation of the diesel engine with the injection hole cross-sectional shape of No. 1, and the intended purpose could not be achieved.

Also, in order to improve the startability and the stability of combustion at low speed, if a glow plug etc. is provided as a heating element in the auxiliary combustion chamber, in order to exert its effect better, It is desirable to directly hit the plug etc., for that purpose, the claw plug etc. should be projected into the auxiliary combustion chamber,
It is necessary to place a part of the inner wall of the auxiliary combustion chamber so that part or all of the glow plug etc. is located in the spot facing part. There is a problem in that the flow and flame propagation are obstructed, the combustion state deteriorates, smoke is easily generated, and this also causes a large decrease in output. Further, it is technically extremely difficult to dispose a heating element in a part or the whole of the inside of the auxiliary combustion chamber in order to control combustion.

Further, the one in which the three-way catalyst is carried on the inner surface of the auxiliary combustion chamber has a problem that the durability of the catalyst is poor.

(Means for Solving the Problems) In view of the above, the present invention provides an internal combustion engine with high output and low pollution by optimizing the amount of air flowing into the auxiliary combustion chamber and the strength of the vortex flow. A nozzle member having a communication hole is formed of a ceramic material, a sub-combustion chamber member that forms a swirl chamber is formed of a ceramic material or a heat-resistant alloy material, and a ceramic sleeve fitted to the cylinder bed is used. The sub-combustion chamber member is rotatably mounted, the opening cross-sectional area to the communication hole is varied, the engine characteristics are controlled, and the sub-combustion member is rotated, airtightness and non-lubricating slidability It is characterized by improving.

〔Example〕

 Examples of the present invention will be specifically described below with reference to the drawings.

In the internal combustion engine shown in FIG. 1, a piston 1 is provided with a main combustion chamber 2, and a cylinder head 3 is provided with a cooling water passage 4, a nozzle hole member 5 made of the ceramic material, and the cylinder head 3. A sub-combustion chamber member 7 made of a ceramic material or a heat-resistant alloy material is mounted via a ceramic sleeve 6 fitted in the recess, and a combustion injection nozzle 10 is attached to the sub-combustion chamber member 7 via a glow plug 8 and an injection port 9. Is equipped with. The injection hole member 5, the ceramic sleeve 6, and the auxiliary combustion chamber member 7 are made of silicon nitride, sialon, or the like as a ceramic material, and the auxiliary combustion chamber member 7 is rotated through the ceramic sleeve 6 fitted in the recess of the cylinder head 3. The auxiliary combustion chamber member 7 is movably supported, and an auxiliary combustion chamber rotating shaft 11 is fixed to the auxiliary combustion chamber member 7 in the axial direction.

On the other hand, by rotating the auxiliary combustion chamber rotating shaft 11 fixed to the auxiliary combustion chamber member 7 from the outside, the opening 12 formed in the auxiliary combustion chamber member 7 is appropriately made by the communication hole 13 formed in the injection hole member 5. The cross-sectional area of the opening 12 is variably controlled by blocking.

Further, the auxiliary combustion chamber member 7 rotatably supported by the ceramic sleeve 6 fitted in the concave portion of the cylinder head 3 so as not to impair the heat insulation effect, is inserted through the seal ring 14 together with the injection hole member 5. The clearance between the ceramic sleeve 6 and the ceramic sleeve 6 is set to be extremely small.
The cylinder head 3 is fitted into the cylinder block 16 through the head gasket 15 to assemble the engine. Therefore, even in the sub-combustion chamber member 7 which rotates at a high temperature, it does not cause seizure or the like and smoothly slides without lubrication, and the airtightness is kept high.

As described above, in the sub-combustion chamber member 7 mounted via the ceramic sleeve 6, the amount of air flowing into the swirl chamber 17 and the strength of the swirl of high-pressure air in the swirl chamber 17 are controlled, and the main combustion is further performed. In order to control the combustion gas flowing out into the chamber 2, the auxiliary combustion chamber rotating shaft 11 is externally rotated in response to the load and the engine speed of the engine, and the opening 12 is formed into the communication hole 13 formed in the injection hole member 5.
The cross-sectional area of the opening 12 is variably controlled by appropriately shielding by, for example, in a low rotation no-load state, as shown in FIG. Stability and good startability are achieved.

Further, in the partial load state of the engine, it acts so that the cross-sectional area of the opening 12 becomes small as shown in FIG. 3, and in the full load state of the engine as shown in FIG. Since the cross-sectional area of the opening 12 is maximized because it is necessary to insert the engine, the engine in the optimum combustion state can be controlled according to the situation.

〔The invention's effect〕

As described above, according to the internal combustion engine of the present invention, the sub-combustion chamber member that maintains a high heat insulating effect and high airtightness in response to the load and the engine speed of the engine is smoothly slid and opened. Since the cross-sectional area of can be made variable and the engine can be controlled, even if a heating element or the like is provided in the sub-combustion chamber, the high-temperature high-pressure air and the injected fuel can be mixed without damaging or disturbing the vortex flow. A proper premixed gas can be generated, the air utilization rate is greatly improved, and the optimum combustion is performed, so the generation of smoke is reliably suppressed, which in turn significantly reduces the amount of particulate emissions in exhaust gas. Improvement of combustion efficiency and reduction of output loss are realized. Furthermore, the ignition delay time is also reduced and reliably realize reduced and thermal load is reduced noise, can reduce the generation amount of the NO _X is therefore optimal harmful substances with decreasing combustion temperature, low cost and mass production It is possible to obtain a high-power, low-pollution internal combustion engine equipped with a sub-combustion chamber suitable for.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a main part showing a structure of an internal combustion engine according to an embodiment of the present invention, and FIGS. 2, 3, and 4 are openings of a sub combustion chamber member in the internal combustion engine according to an embodiment of the present invention. It is a principal part bottom view for explaining a state. 2 ... Main combustion chamber, 3 ... Cylinder head, 6 ... Ceramic sleeve, 7 ... Sub-combustion chamber member, 11 ... Sub-combustion chamber rotating shaft, 12 ... Opening, 13 ... Communication hole.

Claims (1)

[Claims] 1. A sub-combustion chamber member is rotatably mounted in a ceramic sleeve fitted in a cylinder head, the opening cross-sectional area of the sub-combustion chamber member is varied, and engine characteristics are controlled. Characterized internal combustion engine.