JP2541881Y2 - Injection nozzle for forming auxiliary combustion chamber of diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a nozzle hole for forming a sub-combustion chamber which is fitted to a head block of a diesel engine.

<Prior Art> As this type of injection hole nozzle, for example, a nozzle denoted by reference numeral 3 in FIG. 4 is conventionally known.

The nozzle hole base 3 is made of a cast member, forms the upper half 2a of the sub-combustion chamber 2 from the mounting surface 1a of the head block 1 of the engine E to the cylinder block 10, and has an opening 2c in the opening 2c. Is fitted to form the lower half 2b of the sub-combustion chamber 2. An injection hole 5 that connects the sub-combustion chamber 2 to the main combustion chamber 6 is formed in the injection hole base 3 in an inclined manner.
The lower end face of the head block 1 is opened facing the main combustion chamber 6 in a state flush with the mounting face 1a of the head block 1.

In FIG. 4, reference numeral 9 denotes a fuel injection nozzle, 11 denotes a cylinder, and 12 denotes a piston.

<Problem to be Solved by the Invention> By the way, the mounting surfaces of the head block 1 and the cylinder block 10 are flattened with high precision, respectively. It is common to process. This is because it is necessary to control the dimensions so that the end face 3a of the injection hole porthole 3 on the main combustion chamber side does not travel over the assembly surface 1a and does not retract too much.

When the flat surface is processed in this manner, burrs are formed on the inner peripheral edge 5a of the injection hole 5 on the end face 3a of the injection hole die 3, and this is removed, and the inner peripheral edge 5a is removed, for example, from 0.1R to 0R. .
It is necessary to finish the section into an arc shape of about 5R. If the arc-shaped cross section of the injection hole 5 is less than 0.1R, cracks are likely to occur, and destruction occurs due to overheating in the combustion process. .

However, finishing the inner peripheral edge portion 5a of the injection hole 5 is difficult, and is a laborious operation even for a skilled person.

The present invention has been made in consideration of such circumstances.
It is an object to eliminate finish processing of the inner peripheral edge of the injection hole.

<Means for solving the problem> The present invention has been made to solve the above problems,
It is configured as follows.

That is, a nozzle hole for forming a sub-combustion chamber fitted to the head block (1) of the diesel engine (E),
A recess (4) is formed in the main combustion chamber side end surface (3a) in a paragraph shape, and an injection hole (5) is opened inside a deep end surface (4a) of the depression (4). The inner peripheral edge (5a) of the open end of (4) is the deep end face (4a) of the recess (4) over the entire circumference.
Is formed inside the peripheral portion (4b) of the slab and is formed in an arc-shaped cross section, and a wire mesh (8) is arranged in the sub-combustion chamber (2) or the injection hole (5), and the main combustion is performed on the wire mesh (8). The air flow from the chamber (6) is configured to pass therethrough.

The present invention can be carried out regardless of whether the auxiliary combustion chamber is a vortex type or a preheating chamber type.

<Function> The inner peripheral edge 5a of the opening end of the injection hole 5 is located inside the peripheral edge 4b of the deep end surface 4a of the concave portion 4 over the entire circumference, so that the injection hole base 3 is head-blocked. When the assembling surface 1a is flattened in a state where it is fitted to the surface 1, even if burrs occur along the periphery of the lower end surface (the lower end surface in FIG. 1) of the recessed portion 4, No burrs occur on the inner peripheral edge 5a of the injection hole 5, and the arc-shaped portion (R) formed on the inner peripheral edge 5a is not deformed. That is, the arc-shaped portion (R)
Is processed with high precision so that air can quickly flow from the main combustion chamber 6 to the injection hole 5 without being disturbed in the compression step. However, since it is not deformed by the flat processing of the mounting surface 1a as described above, The arc-shaped portion (R) remains in an appropriate shape even if high-precision finishing is not performed after the above-described assembling surface 1a is planarized. This prevents the shape of the arc-shaped portion (R) from varying for each engine due to the planar processing of the mounting surface 1a. The finishing process for removing burrs (burrs) generated on the peripheral edge of the lower end surface of the recessed portion 4 does not require high-precision processing, so the work is simple and does not require much labor.

Further, the airflow from the main combustion chamber 6 is arranged in the sub-combustion chamber 2 or the injection hole 5 of the wire mesh 8, and the airflow from the main combustion chamber 6 passes through the wire mesh 8, so that the injection hole 5 and the auxiliary combustion chamber are moved from the main combustion chamber 6 in the compression step. When the air that has flowed into 2 has passed through the wire mesh 8, a small vortex is generated by the wire mesh 8 and is appropriately disturbed to promote mixing with the fuel. Then, even when the flat surface processing of the assembly surface 1a is performed as described above, the shape of the arc-shaped portion (R) of the injection hole 5 is maintained without being deformed. Is ensured that they flow quickly without disturbance. by this,
A stable turbulence in the air flow in the sub-combustion chamber 2 due to the wire mesh 8 can be obtained without variation for each engine.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a longitudinal sectional view of the periphery of a vortex auxiliary combustion chamber (hereinafter simply referred to as a sub-chamber) of a diesel engine, and FIG.
It is a bottom view of the nozzle hole nozzle in a figure.

In FIG. 1, the upper half 2a of the sub-chamber 2 is formed in the head block 1 of the engine E from its mounting surface 1a in a hemispherical shape, and the injection hole base 3 made of a cast member is fitted into the opening 2c. The lower half 2b of the sub-chamber 2 is formed, and the upper half 2a and the lower half 2b form the sub-chamber 2
Is formed.

The nozzle hole base 3 has a concave portion 4 formed in a stage shape on the main combustion chamber side end surface 3a, the lower end surface of the injection hole 5 facing the deep end surface 4a of the concave portion 4, and the injection hole 5 on the deep end surface 4a. The inner peripheral edge 5a is cast and formed so as to have an appropriate cross-sectional arc shape.

That is, the outer peripheral portion of the injection hole 5 facing the main combustion chamber 6 is
When the assembling surface 1a of the head block 1 is machined into a plane, the arc-shaped cross section formed at the inner peripheral edge 5a of the injection hole 5 is left as it is. Incidentally, the arc shape is formed in a range of 0.1 mmR to 0.5 mmR.

The injection hole 5 is inclined upward and rearward so that its axis goes toward the center of the main combustion chamber 6, and communicates the main combustion chamber 6 with the sub chamber 2. As shown in FIG. 2, the lower end surface of the injection hole 5 looking into the inner end surface 4a of the concave portion 4 is formed with a bulging portion 5c so as to form a substantially mountain shape toward the center of the main combustion chamber 6, and The end face of the injection hole 5 facing the chamber 2 has a substantially circular shape, so that the air on the side of the main combustion chamber 6 smoothly flows into the sub chamber 2 in the compression step, and the flame into the main combustion chamber 6 in the combustion step. It is configured to average propagation and eliminate combustion lag.

In FIG. 1, a wire mesh 8 formed of a metal material having a high melting point such as tungsten is disposed at a boundary between the upper half 2a and the lower half 2b of the sub-chamber 2, and is fixed by being pressed down by the injection hole base 3. ing. The wire mesh 8 promotes mixing with fuel by appropriately disturbing the air flowing into the sub-chamber 2 in the compression process, and also appropriately disturbs the flame flowing out to the main combustion chamber 6 in the combustion process, so that the flame spreads. To smooth out. This improves combustion, improves ignition delay and diesel knock,
It is possible to improve the performance of the engine and reduce noise and vibration.

FIG. 3 shows another embodiment in which the wire mesh 8 is arranged in the middle of the injection hole 5, and the operation and effect are the same as those described above. The required number of the wire meshes 8 can be appropriately arranged on the side closer to the sub chamber of the injection hole 5 or on the side closer to the concave portion 4.

In the above embodiment, the vortex chamber type sub-combustion chamber has been exemplified. However, the present invention is not limited to this, and the present invention can be similarly applied to a preheating chamber type.

<Effect of the invention> In the present invention, the wire mesh is arranged in the sub-combustion chamber or the injection hole, and the airflow from the main combustion chamber passes through the wire mesh.
After passing through the wire mesh, a small eddy flow is generated, and the air flow in the sub-combustion chamber is appropriately disturbed, and the mixing with the fuel is promoted. This improves combustion in the combustion process, improves ignition delay and diesel knock, improves engine performance,
Noise and vibration can be reduced.

Moreover, even if the mounting surface is flattened while being fitted to the nozzle hole head block, burrs are not generated at the inner peripheral edge of the opening end of the nozzle hole. Even if high-precision finishing is not performed after machining, the arc-shaped portion (R) of the injection hole of proper shape can be reliably maintained, so that air can quickly flow from the main combustion chamber to the injection hole without being disturbed. It is ensured by the engine, and a stable turbulence of the airflow in the sub-combustion chamber due to the wire mesh can be obtained without variation for each engine, so that the quality of the combustion performance of the diesel engine can be made uniform.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view around an eddy current type auxiliary combustion chamber, FIG. 2 is a bottom view of a nozzle hole nozzle in FIG. 1, and FIG. FIG. 4 is a vertical sectional side view showing another example of the injection hole nozzle, and FIG. 4 is a vertical sectional side view of a main part of a diesel engine according to a conventional example. E ... Diesel engine, 1 ... Head block, 2
... Sub-combustion chamber, 3... Nozzle hole, 3a... Main combustion chamber side end face, 4... Recessed section, 4a. Peripheral edge, 4b: Peripheral edge of inner end face of recess, 6: Main combustion chamber, 8: Wire mesh.

Claims (1)

(57) [Scope of request for utility model registration] 1. A nozzle hole for forming a sub-combustion chamber which is fitted to a head block (1) of a diesel engine (E), wherein a concave portion (4) is formed in the main combustion chamber side end surface (3a) in a paragraph-like manner. The injection hole (5) is opened inside the inner end surface (4a) of the recess (4), and the inner peripheral edge (5a) of the opening end of the injection hole (5) is End face (4a) of the recess (4)
A wire mesh (8) is formed inside the peripheral edge portion (4b) of the sub-combustion chamber (2) or in the injection hole (5).
A nozzle hole for forming a sub-combustion chamber of a diesel engine, wherein an airflow from the main combustion chamber (6) is passed through the wire mesh (8).