JP2567875Y2 - Spark ignition gas engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for forming a torch by a sub-chamber shape of a spark ignition gas engine.

[Conventional technology]

 A conventional example will be described with reference to FIGS.

In these conventional examples, gas fuel having a mixture ratio that facilitates ignition is introduced into the sub-chamber 60, and a spark plug installed in the sub-chamber is provided.
Ignited by 80, to form a torch into the main combustion chamber by the flame is ejected from the auxiliary chamber injection port 61, usually burned by the spark hard lean gaseous fuel, so as to reduce the occurrence of the NO _x .

4 and 5 show the shape of a sub chamber of a conventional torch ignition gas engine with a sub chamber, and FIG.
FIG. 5 shows an example of a cylindrical type. In each of the torch sub-chambers 60, the position of the ignition plug 80 is directly affected by the lean mixture flow in the main combustion chamber flowing from the injection port 61 during the compression process. It is installed in.

[Problems to be solved by the invention]

However, in the conventional example, when there is no flow of the air-fuel mixture in the sub-chamber, the flame spreads from around the spark plug 70,
It is said that a strong torch cannot be formed because unburned gas is first blown out from the nozzle 61 and then a flame is blown out.
Therefore, it is considered a good method to positively generate a vertical swirl flow of the air-fuel mixture, and to cause the ignited flame to flow into the main combustion chamber relatively quickly on the swirl flow to form a powerful torch. . As a method for generating this swirling flow, the fourth method
Examples of the spherical sub-chamber in the figure and the nozzles in FIGS. 6 and 7 are shown. On the other hand, the air-fuel mixture near the spark portion of the spark plug 80 preferably has a mixing ratio that facilitates ignition and has less flow, and it is difficult to perform stable ignition with a strong air-fuel mixture.

The purpose of the present invention is to solve the above conventional apparatus, suppress the generation of a stable powerful torch is formed NO _x in the flame with ignition is performed in the longitudinal swirling flow of the secondary chamber into the main combustion chamber propagates To provide a spark ignition gas engine.

[Means for solving the problem]

The spark ignition gas engine of the present invention has a sub-chamber at substantially the center of the cylinder head, has a passage through which an air-fuel mixture for ignition flows from the upper part of the sub-chamber, and further ignites in the sub-chamber by a spark plug to perform main combustion In the spark ignition engine that forms a torch in the room, a throat-like passage whose cross section is narrowed in an arc shape is provided in front of the ignition plug in the sub-chamber, or a shelf-like projection is provided in front of the torch gas supply port. It is characterized in that it is provided in a direction perpendicular to the axis of the sub chamber.

[Action]

Since the spark ignition gas engine of the present invention is configured as described above, a stable mixture is ensured by forming a rich mixture having a small flow near the spark plug, and the flame is turned into a strong swirling flow in the sub-chamber near the main combustion chamber. Is propagated to form a powerful torch, so that the lean mixture in the main combustion chamber stably burns
Generation of NO _x can be suppressed as much as possible.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment of the present invention.
Is a throat portion 65a formed by squeezing an intermediate portion of the slab so that the cross section becomes an arc shape. Sub chamber by the throat part 65a
60 is divided into an upper chamber 21 and a lower chamber 22, and the upper chamber 21 is formed in a small volume. An ignition plug 80 is provided at the upper end of the center of the upper chamber 21, and a small amount of fuel gas is introduced along the center line of the ignition plug 80 into the upper chamber 21 on the side thereof. A torch gas passage 90 is provided. The volume of the small volume upper chamber 21 is 3 times of the total stroke volume.
About 5%. 23 is a main combustion chamber, and 61 is a nozzle of the sub chamber 60.

 Next, the operation of the first embodiment will be described.

In the compression stroke of the piston, the lean mixture in the main combustion chamber flows from the injection port 61 of the sub-chamber 60 into the sub-chamber 60, and the air-fuel mixture generates a swirling flow in the sub-chamber 60. However, by forming the throat portion 65a whose section is narrowed in an arc shape above the center of the sub-chamber, a flow such as a vertical swirling flow is generated in the lower chamber, while relatively gentle near the spark plug in the upper chamber. A rich mixture with less turbulence is formed by a smooth flow and stable ignition is obtained, and a torch flame from the upper sub-chamber provides a gentle flame with less turbulence to the lean mixture in the lower sub-chamber. is possible and to form a reliable torch jet into the main combustion chamber, it is possible to minimize the occurrence of complete combustion is not NO _x lean mixture in the main combustion chamber.

FIGS. 2 and 3 show a second embodiment of the present invention, which is characterized in that a shelf-like projection 65b is provided at the installation position of the throat portion in the first embodiment in a direction perpendicular to the axis of the sub-chamber 60.

In the second embodiment, an auxiliary gas for ignition (torch gas) is used.
The auxiliary gas for ignition from the outlet of the passage 90 does not collide with the air-fuel mixture flowing from the injection port 61 below the sub-chamber 60, and
In the vicinity of 80, the mixture formed by generating a gentle swirling flow from the auxiliary gas supply hole to the spark plug in the upper sub-chamber by the gentle flow from the lower sub-chamber is stably ignited. , The flame propagates to the flowing mixture below,
This causes a flame to be blown out from the nozzle 61 into the main combustion chamber 23. Other configurations are the same as those of the first embodiment, and the same members are denoted by the same reference numerals.

[Effect of the invention]

In the first aspect of the present invention, since the sub-chamber throat portion whose cross section is narrowed in an arc shape is provided, the flow from the sub-chamber lower part is suppressed in the sub-chamber upper chamber, and the flow inside is gentle with little disturbance. As a result, the auxiliary gas for ignition flows without being disturbed and greatly expands, and flows near the spark plug to form a stable rich mixture, and stable ignition is performed. Propagation, and therefore, formation of a powerful torch that propagates the flame to the swirled air-fuel mixture can be expected in the sub-chamber lower chamber, and stable flame propagation can be ensured even if the air-fuel mixture in the main combustion chamber is lean. NO _x generation can be suppressed to a low level.

Further, in the second aspect, a shelf-shaped projection is provided in the throat portion of the sub-chamber of the first aspect, so that a small amount of fuel gas to be injected flows near the spark plug in the upper chamber and a rich air-fuel mixture is stored, so that the upper chamber is stabilized. Ignition can be expected. In addition, a lean mixture that forms a vertical swirling flow and flows in is also prevented by the ledges,
Since there is no direct collision with the ignition auxiliary gas, the flow of the ignition auxiliary gas near the auxiliary plug is not hindered. Therefore, a strong torch is formed in which stable ignition is performed and the flame is propagated to the vertical swirling flow in the lower sub chamber, and complete combustion of the lean mixture and NO _x generation in the main combustion chamber can be suppressed to a low level. .

[Brief description of the drawings]

FIGS. 1 to 3 relate to the present invention. FIG. 1 is a sectional view of the vicinity of a sub-chamber and a main combustion chamber of the first embodiment. FIG. 2 is a drawing corresponding to FIG. The figure is a sectional view taken along the line III-III in FIG.
4 to 7 show a conventional example, FIG. 4 is a longitudinal sectional view around a sub-chamber of the first conventional example, FIG. 5 is an arrangement diagram of FIG. 4 of the second conventional example, and FIGS. It is a figure which shows the row of the nozzle hole of asymmetric arrangement | sequence which produces | generates a vertical swirl flow by the inflow-air mixture in a compression stroke. 21: Upper chamber of sub chamber, 22: Lower chamber of sub chamber, 23: Main combustion chamber, 60: Sub chamber, 65a: Throat, 65b: Shelf-shaped projection, 80: Spark plug , 90 …… Auxiliary gas passage for ignition (torch gas passage).

Continuation of front page (56) References JP-A-51-129508 (JP, A) JP-A-52-106009 (JP, A) JP-A-54-86007 (JP, A) JP-A-2-81925 (JP) JP-A-54-126805 (JP, A) JP-A-56-67373 (JP, U) JP-A-49-23603 (JP, U) JP-A-2-67031 (JP, U)

Claims (2)

(57) [Scope of request for utility model registration] 1. A sub-chamber is provided substantially at the center of a cylinder head.
And in a spark ignition engine having a passage through which an auxiliary gas for ignition flows from the upper part of the sub-chamber, and further igniting in the sub-chamber by a spark plug to form a torch into the main combustion chamber,
A spark ignition gas engine, characterized in that a throat-like passage whose section is narrowed in an arc shape is provided in front of the ignition plug in the sub-chamber. 2. A sub-chamber substantially at the center of the cylinder head,
And in a spark ignition engine having a passage through which an auxiliary gas for ignition flows from the upper part of the sub-chamber, and further igniting in the sub-chamber by a spark plug to form a torch into the main combustion chamber,
A spark ignition gas engine in which a shelf-like projection is provided in front of the auxiliary gas supply port for ignition in a direction perpendicular to the axis of the sub-chamber to form a rich air-fuel mixture near the spark plug.