JPH0584364B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a diesel internal combustion engine, and in particular, it is possible to effectively control the swirl generated from high-temperature, high-pressure air introduced into a swirl combustion chamber and the fuel injected into the swirl. The present invention relates to a vortex combustion chamber that improves ignitability and slow combustion.

[Prior art] Conventionally, during low load conditions such as idling, the injected fuel vapor is slowly released,
A proposal was made in Japanese Patent Application No. 193477-1983 to make the fuel slower and significantly reduce noise and vibration.

In this proposal, a passage is formed facing the vortex combustion chamber, and an injection nozzle having a main injection hole for injecting fuel into the combustion chamber is provided in the passage, and the injection nozzle is branched from the main injection hole during low load. A sub-nozzle which is opened by closing the main nozzle is provided in the main nozzle, and the ejection end of the sub-nozzle is arranged so that the fuel injected from this flows along the inner wall of the combustion chamber in the downstream direction of the swirl, and the inner wall thereof. The fuel injected from the sub-nozzle collides with the communication port to form an atomized spray, while the fuel injected from the sub-nozzle collides with the communication port to form an atomized spray. The fuel evaporates from the mouth along the inner wall of the combustion chamber to form a fuel film, and the atomized spray near the nozzle is evaporated by the swirl generated from high-temperature compressed air and becomes a premixed vapor with high ignitability. Ru. This was ignited, flame propagated to the fuel film, and was slowly combusted to transmit driving force to a piston in a cylinder communicating with the swirl combustion chamber.

[Problems to be solved by the invention] However, in the above proposal, during low load such as idling, fuel is injected from the sub-nozzle along the combustion chamber to form an evaporated premixture. , thereby shortening the ignition time and
Noise is significantly reduced by slowly burning the fuel film, but in order to achieve even greater evaporative combustion, it may be possible to strengthen the swirl, that is, the swirl pushed into the vortex combustion chamber. However, on the other hand, the swirl and fuel are not mixed effectively, which not only deteriorates the combustion state and generates smoke etc., but also becomes a major factor in reducing output.

[Object of the Invention] The present invention was devised to solve the above-mentioned problems, and an object of the present invention is to form a strong swirl in the combustion chamber and to mix it with the fuel injected into the swirl to improve the quality of the swirl. The aim is to provide a vortex combustion chamber to achieve combustion.

[Summary of the Invention] In order to achieve the above object, the present invention provides a fuel injection nozzle that faces a vortex combustion chamber and is provided with a main injection port and a sub-injection port via a communication passage. The main nozzle is closed and only the auxiliary nozzle is opened during low load, including when the main nozzle is closed, and the fuel injected from the main nozzle passes through the communication passage and directly reaches the swirl combustion chamber. In addition, the sub-nozzle is provided close to the inner wall surface of the communication passage, and the fuel injected from the sub-nozzle is injected into the vortex combustion chamber so as to collide with the inner wall surface of the passage. A shelf-shaped protrusion is provided on the inner wall of the combustion chamber only at a portion that intersects with the center axis of the swirl generated within the vortex combustion chamber.

[Example] Hereinafter, a preferred example of the present invention will be described based on FIG. 1.

As shown in FIG. 1, reference numeral 2 denotes a swirl combustion chamber defined in the cylinder head 1;
, a compressed air swirl S is generated. For example, a nozzle holder 3 is fitted into one side of the combustion chamber 2 facing the combustion chamber 2, and is provided with a fuel injection nozzle 20 that guides the throttle valve 4 in a vertically movable manner. A main injection port 9 is provided to inject fuel into the combustion chamber 2 along the combustion chamber 2 . Further, the main nozzle 9 is provided to eject fuel along the swirl direction introduced into the combustion chamber 2, and above the main nozzle 9, the diameter of the main nozzle 9 is sequentially expanded outward in the radial direction. The valve seat 10 is tilted to form an inclined valve seat 10. On the other hand, the throttle valve 4 includes a throttle shaft part 5 for moving up and down along the nozzle holder 3, a tapered part 6 for seating and opening/closing by engaging with the valve seat 10, and a throttle part 6 for sliding on the main nozzle 9. A nozzle head 7 that fits freely to form an injection bundle of fuel ejected from the nozzle head 7, and a nozzle head 7 whose diameter is gradually expanded upward from the valve seat 10 and radially outward along its axis. It is mainly composed of a tapered pressing section (not shown). Throttle valve 4 like this
is formed so that the taper portion 6 is always seated and engaged with the valve seat 10 by a biasing means (not shown) such as a spring.

On the other hand, in order to bias the throttle valve 4 in the opening direction when the taper part 6 is seated, the nozzle holder 3 is formed with an annular part with an enlarged diameter so as to surround the taper pressing part. The fuel pressure supplied to the taper press section applies a pressing force in the valve opening direction, thereby separating the throttle valve 4 from the valve seat 10, and the fuel flows into the main injection port in proportion to the degree of separation. It will be injected from 9.

On the other hand, the throttle valve 4 is mounted on the valve seat 10.
The sub-nozzle 14 is located below the valve seat surface on which the main nozzle 9 is seated, and is branched from the main nozzle 9 to form a sub-nozzle 14, one end of which is open from the valve seat surface, and the other end of which is connected to the inner wall of the communication passage 13 above the combustion chamber 2. It is provided with an opening facing 13a so that the fuel jetted from the opening collides with it and is atomized.

In the swirl combustion chamber 2 configured as described above,
In order to efficiently burn the fuel injected from the main nozzle 9 and the auxiliary nozzle 14 at high and low loads with good ignition and slow combustion, the swirl of high-temperature and high-pressure air introduced into the combustion chamber 2 is attenuated. In order to mix the fuel injected from the jet port without causing any turbulence, a shelf-like protrusion 16 that generates turbulence is provided on the inner wall 15 of the combustion chamber 2 facing in the direction of the central axis of the swirl. . The protrusion 16 is provided on the inner wall 15 of the combustion chamber 2 within a range of 45 degrees left and right with the direction of the swirl introduced from the communication passage 13 of the vortex combustion chamber 2 as an axis, avoiding the swirl introduced. Further, as shown in FIG. 2, the protrusions 16 are provided on both walls so as to sandwich the injection bundle of fuel, and are formed to generate turbulent flow and mix the fuel effectively even during high swirl.

The swirl introduced into the combustion chamber 2 swirls along the inner wall 15 on the upstream side when the load is high, and collides with the protrusion 16 on the downstream side to form a turbulent flow around it.

Therefore, the swirl is disturbed by the protrusion 16, and since the fuel flows along the inner wall 15, the fuel evaporated from the wall surface and the atomized fuel effectively generate a premixture, which flows into the combustion chamber 2. to form a fuel film F distributed along the inner wall 15 of the
The ignition is ignited from the periphery of the throttle valve 4 by the high temperature of the compressed air, and the fire spreads, causing the fuel film F to burn slowly one after another. Further, even when the fuel film F is ignited and burned under high load, and a fuel with a large diameter and large penetration force is injected from the main nozzle 9, the protrusion 1
Since the swirl S is disturbed by the swirl S of high-temperature compressed air, the swirl S is mixed and evaporated, and furthermore, the fuel that reaches the inner wall 15 is already in an ignited combustion state, so the fuel is propagated by fire. It ignites and burns to achieve slow combustion that does not generate smoke, etc., and significantly reduces noise.

[Effects of the Invention] As described above, the present invention exhibits the following excellent effects.

(1) A fuel injection nozzle is provided to supply fuel to the vortex combustion chamber of the cylinder head that generates swirl, and a shelf-shaped nozzle is installed on the inner wall of the vortex combustion chamber only at the portion that intersects with the center axis of the swirl of the vortex combustion chamber. The provision of the protrusion dramatically improves the mixing properties of air and fuel, and achieves quiet, slow combustion that prevents diesel knock.

(2) It is possible to suppress the generation of smoke, improve combustion efficiency, and reduce output loss.

(3) Smoke suppression prevents the formation of carbonized products, which improves engine reliability.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a preferred embodiment of the present invention, and FIG. 2 is a detailed sectional view of the main part of FIG. In the figure, 1 is the cylinder head, 2 is the swirl combustion chamber,
13 is a communication passage, 16 is a protrusion, and 20 is an injection nozzle.

Claims (1)

[Claims] 1 A fuel injection nozzle 20 including a main nozzle 9 and a sub-nozzle 14 is connected to the communication passage 1 facing the vortex combustion chamber 2.
3, installed through the fuel injection nozzle 20
is configured to close the main nozzle 9 and open only the auxiliary nozzle 14 during low load including when the engine is idling, and the fuel injected from the main nozzle 9 passes through the communication passage 13, The fuel directly reaches the swirl combustion chamber 2, and the sub-nozzle 14 is provided close to the inner wall surface 13a of the communication passage, and the fuel injected from the sub-nozzle 14 collides with the inner wall surface 13a of the passage. In the whirlpool combustion chamber where the jet is injected, on the inner wall of the whirlpool combustion chamber 2,
A vortex combustion chamber characterized in that a shelf-shaped protrusion 16 is provided only in a portion intersecting with the central axis of the swirl generated within the vortex combustion chamber.