JP2874286B2 - Fuel collision diffusion engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel collision diffusion engine in which fuel injected from a fuel injection nozzle directly collides with a projection provided in a combustion chamber.

[Conventional technology]

Conventionally, a combustion chamber of an engine is represented by a direct injection type and a sub chamber type.

The direct injection combustion chamber achieves mixing of fuel and air by the injection energy of the fuel injected from the fuel injection nozzle and swirl and squish flows formed in the combustion chamber, thereby forming a combustible air-fuel mixture. However, the direct injection combustion chamber has a problem that intake efficiency is reduced due to swirl generation, and a high pressure fuel injection nozzle is used to increase atomization and penetration of fuel.
It must be configured to have a high injection rate, and has a problem that the structure becomes complicated.

In addition, the sub-chamber combustion chamber achieves mixing of fuel oil droplets and air by a high swirl formed in the sub-chamber to form a combustible air-fuel mixture. The sub-chamber type combustion chamber has a problem that a high swirl is formed in the sub-chamber, the total heat transfer area of the main chamber and the sub-chamber increases, and the heat loss increases. This causes a problem that the throttle loss due to the communication hole communicating with and increases.

In order to solve the above problem, a direct injection collision diffusion stratified charge system using a fuel impinging jet, so-called O
An engine having an SKA type combustion chamber is disclosed. OSKA
The type engine has a recess formed in the piston, that is, a collision portion protruding from the center of the bottom of the cavity, forms a concave combustion chamber around the collision portion, and collides the liquid fuel injected from the fuel injection nozzle with the collision portion. The fuel jet collides with the colliding portion to achieve diffusion and atomization of the fuel starting from the collision surface, thereby achieving good mixing of the fuel and air.

In the engine having the combustion chamber as described above, the fuel injected from the single-hole nozzle of the fuel injection nozzle collides with the flat collision surface of the collision portion of the piston head and is diffused in a disk shape. The fuel and air are mixed together to form a mixture while being pushed below the cavity by the squish flow generated by the ascent.

Japanese Patent Application Laid-Open No. Sho 62-195408 discloses a diesel engine based on collision reflection diffusion of a fuel jet.
The first phase of the diesel engine starts from the injection hole of the fuel injection nozzle, and the first period is when the fuel jet reaches the jet impingement surface in the cavity, and the second period is when the fuel part deflected by the collision surface reaches the cavity wall surface. The second period is defined as the period during which the fuel that has reached the wall surface evaporates and vaporized, and the third period is used to cause a combustion reaction in each period. The fuel jet from the nozzle collides with the collision surface in the cavity. The collision surface is formed in a polygonal shape so that the fuel can be diffused in an arbitrary direction by a reaction.

Further, Japanese Patent Application Laid-Open No. 62-240419 discloses a direct injection diesel engine. The direct injection diesel engine completes the fuel injection from the fuel injection valve before the compression ignition is performed so that the liquid fuel adheres to the inner peripheral wall surface of the cavity formed on the piston top surface. The fuel collision wall on the inner peripheral wall of the cavity has a flat circular central portion, a substantially conical projection formed at the center of the circular central portion, and an inclined surface extending radially from the circular central portion.

[Problems to be solved by the invention]

By the way, in the engine using the piston having the OSKA type combustion chamber, the collision surface for colliding the fuel injected from the single-hole nozzle is a flat collision surface of the piston head.
The fuel collides with the collision surface and is diffused in a disk shape, but the squish flow into the combustion chamber is generated by the upward stroke of the piston, and the squish flow generates a good mixture of thin film disk-shaped fuel and air. To improve the combustion state. However, at partial engine load, NO _x
While the generation is suppressed to some extent, at the time of high load of the engine, the combustion chamber with a high temperature, since the fuel is burned in direct injection type, there is a problem that occurrence of the NO _x increases.

Further, the diesel engine disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 62-195408 by the collision reflection diffusion of the fuel jet and the direct injection type diesel engine disclosed in the Japanese Patent Application Laid-Open No. 62-240419 are also disclosed in the above-mentioned publication. Like things,
During fuel injection, stop the communication hole, the mixing of the squish flow and the fuel into the combustion chamber which is formed in the piston satisfactorily performed, and not to perform the main combustion in the fuel chamber, to suppress the generation of the NO _x No measures have been taken. Moreover, the shape of the collision surface for improving the fuel injection in the combustion chamber is not taken into consideration.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems. A protrusion is formed on a cylinder head, a fuel injection nozzle is disposed at a center of the protrusion, and a combustion chamber formed on a piston head and the combustion chamber are formed. A communication hole is formed for communication between the fuel chamber and the main chamber. A protrusion having a collision surface is arranged in the combustion chamber. Fuel is injected from the fuel injection nozzle provided in the cylinder head to the collision surface, and the injected liquid The fuel collides with the collision surface to uniformly diffuse the disc-shaped fuel film, and the protrusion of the cylinder head is caused to protrude into the communication hole by raising the piston to form the communication hole in the annular passage. The opening area is narrowed, the combustion chamber is configured to have the same function as the sub-chamber, and the flow direction of the air that has flowed in by the squish flow through the annular passage and the fuel injection direction of the fuel that is diffused and injected in a disk shape And Sasa allowed to promote mixing of fuel and air, to reduce the occurrence of the NO _x and to perform the main combustion in fuel-rich in the combustion chamber as a secondary chamber, the unburnt fuel or intermediate made to perform a good combustion It is an object of the present invention to provide a fuel collision diffusion engine that prevents the emission of living organisms.

[Means for solving the problem]

The present invention is configured as follows to achieve the above object. That is, the present invention provides a combustion chamber having an opening formed in a piston head, a projection provided at a substantially central bottom of the combustion chamber and having a collision surface of injected fuel, and a cylinder head itself projecting from a lower surface of the cylinder head. The main chamber and the combustion chamber formed between the protruding portion and the wall surface of the opening in a state where the protruded portion and the protruding portion protrude into the opening of the combustion chamber near the top dead center. An annular passage communicating therewith, and a fuel injection nozzle having an injection port disposed in the protrusion and opened to face the protrusion, wherein the annular passage has the protrusion at a piston top dead center and the combustion chamber. The squish flow flowing from the main chamber into the combustion chamber through the annular passage is narrowed by the projection and the peripheral wall of the opening in a state where the squish enters the opening of the fuel injection nozzle. of a body A fuel collision diffusion type engine, characterized in that to promote the mixing intersect the fuel film to diffuse collides with the serial impact surface.

Further, in this fuel collision diffusion type engine, at the time of secondary mixing ejected from the combustion chamber to the main chamber, the opening area of the annular passage increases, and the ejected gas diffuses into the main chamber.

In this fuel collision diffusion engine, the volume of the combustion chamber is the total volume of the compression end at the piston top dead center.
It is comprised between 40% and 60%.

[Action]

Since the fuel collision diffusion engine according to the present invention is configured as described above, the annular passage narrows the maximum diameter of the communication hole, that is, the opening portion of the combustion chamber, and the combustion chamber is substantially a sub-chamber. Will fulfill the combustion function.
In this state, the liquid fuel is injected from the fuel injection nozzle to the collision surface, so that the liquid fuel becomes a disk-shaped film along the collision surface and diffuses into the combustion chamber, and the fuel of the disk-shaped film and the main chamber to the combustion chamber. And a good air-fuel mixture can be generated. In particular, it is not the main combustion fuel rich to achieve good mixing of the air and the disk film-like fuel flowing in the squish flow into the combustion chamber in the combustion chamber, it is possible to suppress the generation of NO _x.

That is, the fuel injected from the injection port of the fuel injection nozzle collides with the collision surface in a liquid state and diffuses radially outward along the collision surface to form a disk-shaped fuel film.
The squish flow guided by the protruding portion can cross the squish flow on the disc-shaped fuel film, so that good mixing of fuel and air can be realized and fuel efficiency can be improved.

〔Example〕

Hereinafter, an embodiment of a fuel collision diffusion engine according to the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view showing an end of a compression step of an embodiment of a fuel collision diffusion type engine according to the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. FIG. 3 is an explanatory diagram showing an initial stage after a top dead center of the collision diffusion engine.

As shown in FIG. 1, this fuel collision diffusion type engine fits into a cylinder block 9, a cylinder head 3 having an intake port 6 and an exhaust port 7 fixed to the cylinder block 9, and a hole of the cylinder block 9. And a main chamber 1 formed by the cylinder liner 14, the lower surface of the cylinder head 3, and the top surface of the piston 15. An intake valve 16 is arranged at the intake port 6, and an exhaust valve 17 is arranged at the exhaust port 7.

The piston 15 is made of a metal material such as aluminum, for example, and a cavity, that is, a combustion chamber 2 is formed in a piston head portion of the piston 15. In particular, the combustion chamber 2 formed in the piston head has a projection 5 extending upward at a substantially central bottom portion. For example, a thin plate made of ceramics such as zirconia (ZrO ₂ ) having a high heat insulating property can be attached to the protrusion 5. The upper portion of the projection 5 extends upward from the bottom surface of the cavity and is located below the surface of the opening 10 of the combustion chamber 2, that is, below the top surface of the piston head. The upper part of the protrusion 5 is formed in a disk part 5P,
The top surface of 5P is formed on a flat collision surface 12. Impact surface 12
Constitutes the surface on which the liquid fuel collides.

Further, the cylinder head 3 is formed with a protruding portion 8 extending downward to face the combustion chamber 2 formed in the piston head portion. The protruding part 8 has an opening near the top dead center of the piston.
It is configured to enter the combustion chamber 2 from 10. A fuel injection nozzle 4 is attached to the center of the protruding portion 8, and the fuel injection nozzle 4 has an injection port 11 facing a collision surface 12 of a projection 5 provided in the combustion chamber 2.

The fuel injection nozzle 4 is formed of a single-hole nozzle such as a piston nozzle, and is configured such that the fuel injected from the injection port 11 of the nozzle collides at the center of the collision surface 12 in a liquid state. Further, the volume of the combustion chamber 2 is configured to be 60% or less, particularly 40% to 60% of the total volume of the compression end at the top dead center of the piston. In addition, since the protrusion 8 provided on the cylinder head 3 protrudes into the opening 10 near the top dead center, the opening 10 becomes an annular passage 13 and the communication area is reduced. Thus the combustion chamber 2 is substantially functions as a secondary chamber, can be performed to suppress combustion generation of NO _x.

Therefore, the protrusion 8 provided on the cylinder head 3 protrudes downward corresponding to the peripheral wall of the opening 10 communicating with the combustion chamber 2 formed on the piston head, and the protrusion 8 near the piston top dead center. And the peripheral wall or wall surface 19 of the opening 10 form an annular passage 13. Therefore, the squish flow generated by the rise of the piston and flowing into the combustion chamber 2 from the main chamber 1 is guided by the outer peripheral surface 18 of the protruding portion 8 and the jet direction is changed as indicated by the arrow, and the squish flow is directed to the wall surface 19 of the combustion chamber 2 It flows downward along. Therefore, the downward flow of the squish flow is enhanced, and the enhanced squish flow is
Intersects the disc-shaped fuel film injected from the orifice, and the mixing of air and fuel is promoted.

The fuel collision diffusion engine according to the present invention is configured as described above, and operates as follows.

In this fuel collision diffusion engine, the projecting portion 8 provided on the cylinder head 3 projects into the opening 10 formed on the piston head portion so that the opening 10 forms an annular passage 13 having a reduced cross-sectional area of the communicating portion. As a result, the combustion chamber 2 has the same function as the sub-chamber. Then, the air in the main chamber 1 flows into the combustion chamber 2 through the annular passage 13 as a squish flow by the rise of the piston 15, but the opening 10 becomes the annular passage 13 and the cross-sectional area is narrowed. The flow is strengthened.

As shown in FIG. 1, fuel injected at low pressure from the injection port 11 of the fuel injection nozzle 4 attached to the cylinder head 3 is converted into a rod-like liquid fuel near the end of the compression stroke in the combustion chamber 2 facing the injection port 11. It collides with the collision surface 12 of the projection 5 and becomes a thin film-shaped disk, which diffuses radially outward. At this time, the squish flow reinforced by raising the piston 15 flows into the combustion chamber 2 through the annular passage 13 while being guided by the outer peripheral surface 18 of the protrusion 8 provided on the cylinder head 3.

Therefore, the squish flow and the disk-shaped thin-film fuel intersect in an orthogonal state to achieve good mixing. In particular, since the primary combustion in the combustion chamber 2 is performed in a closed space with fuel richness, NO _x Can be suppressed, and a good combustion state can be secured to improve the combustion efficiency.

Next, as shown in FIG.
, The cross-sectional area of the passage of the opening 10 rapidly increases, the fire flows out of the combustion chamber 2 to the main chamber 1 at once, and the fuel equivalent ratio rapidly decreases and the combustion temperature rapidly decreases. . Therefore, the combustion state in the NO _x generation region can be avoided, and the generation of NO _x can be further suppressed.

Next, another embodiment of the fuel collision diffusion type engine according to the present invention will be described with reference to FIG. The fuel collision diffusion type engine of this embodiment has exactly the same configuration and function as the above embodiment except that the shape of the main chamber 1 is slightly different. Therefore, in the fuel collision diffusion engine of this embodiment, the same components as those in the fuel collision diffusion engine shown in FIG. 1 are denoted by the same reference numerals, and duplicate description will be omitted. That is, the main chamber 1 in this embodiment has a structure in which the concave portion 20 is formed on the top surface of the piston 15 so that the main chamber 1 is clearly formed.

〔The invention's effect〕

Since the fuel collision diffusion engine according to the present invention is configured as described above, the annular passage narrows the cross-sectional area of the communication hole or opening of the combustion chamber to a smaller extent, and the combustion chamber is substantially subordinate. Function as a room,
When the opening is narrowed, the skinsh flow flowing from the main chamber into the combustion chamber is strengthened.

On the other hand, when the liquid fuel is injected from the fuel injection nozzle to the collision surface, the liquid fuel is diffused into the combustion chamber as a disk-shaped film along the collision surface. Therefore, a good air-fuel mixture can be generated between the fuel of the disc-shaped film and the squish flow air from the main chamber to the combustion chamber. In particular, good mixing of the air flowing into the combustion chamber with a squish flow and the fuel in the form of a disk film is realized, and the fuel-rich main combustion is performed in the combustion chamber.
The generation of the NO _x can be suppressed.

Next, this fuel collision diffusion engine, after top dead center,
In the downward stroke of the piston, the annular passage changes into an opening having a large area, the passage cross-sectional area of the opening suddenly increases, and the jet gas or fire flows out of the combustion chamber to the main chamber at once. As a result, the fuel equivalent ratio rapidly decreases, and the combustion temperature sharply decreases. Therefore, it is possible to avoid the combustion state of occurrence area of the NO _x in the secondary combustion, the generation of the NO _x can be further suppressed. That is, the fuel injected from the fuel injection nozzle collides with the collision surface in a liquid state and diffuses radially outward along the collision surface to form a disk-shaped fuel film. The squish flow can be made to cross the disc-shaped fuel film with the squish flow, and good mixing of fuel and air can be realized, and combustion efficiency can be improved.

In this fuel collision diffusion engine, the volume of the combustion chamber is 40% of the total volume at the compression end at the piston top dead center.
% To 60%, the combustion chamber can function as the most preferable sub-chamber.

[Brief description of the drawings]

1 is an explanatory view showing the end of a compression stroke of one embodiment of a fuel collision diffusion type engine according to the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is a fuel collision shown in FIG. FIG. 4 is an explanatory diagram showing an initial stage of a combustion stroke of a diffusion engine, and FIG. 4 is an explanatory diagram showing another embodiment of a fuel collision diffusion engine according to the present invention. 1 ... Main chamber, 2 ... Combustion chamber, 3 ... Cylinder head, 4 ... Fuel injection nozzle, 5 ... Protrusion, 5P ... Disc section, 8 ... Protruding section,
10 ... opening of combustion chamber, 11 ... nozzle, 12 ... collision surface, 13 ...
... annular passage, 15 ... piston, 20 ... recess.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Sekiyama 8 Dosa, Fujisawa-shi, Kanagawa Prefecture Isuzu Ceramics Research Institute Co., Ltd. (72) Inventor Yoji Sasaki 8 Dosha, Fujisawa-shi, Kanagawa Isuzu Ceramics Co., Ltd. (56) References JP-A-62-139921 (JP, A) JP-A-2-130218 (JP, A) JP-A-55-49521 (JP, A) JP-A-2-115916 (JP, U) (58) Field surveyed (Int.Cl. ⁶ , DB name) F02B 1/00-23/10

Claims (3)

(57) [Claims] 1. A combustion chamber having an opening formed in a piston head, a projection provided substantially at the center bottom of the combustion chamber and having a collision surface of injected fuel, and a cylinder head itself protruding from a lower surface of the cylinder head. A main chamber formed between the protruding portion and a wall surface of the opening in a state where the protruding portion protrudes into the opening of the combustion chamber near a top dead center, and communicates with the combustion chamber. An annular passage, and a fuel injection nozzle provided in the projection and having an injection port opened opposite to the projection, wherein the annular passage has the projection at the top dead center of the piston. In the state of being inserted into the opening, it is narrowed down by the projection and the peripheral wall of the opening,
The squish flow flowing from the main chamber into the combustion chamber through the annular passage intersects with the fuel film diffusing by colliding from the injection port of the fuel injection nozzle with the collision surface of the projection to promote mixing. Features a fuel collision diffusion engine. 2. The secondary mixing jetting from the combustion chamber to the main chamber, the area of the opening increases immediately, and the flame is blown out from the combustion chamber to the main chamber and diffused within a small crank angle. The fuel collision diffusion engine according to claim 1, wherein: 3. The fuel collision diffusion engine according to claim 1, wherein the volume of the combustion chamber is 40% to 60% of the total volume of the compression end at the top dead center of the piston.