JP2584314Y2 - Subchamber structure of lean burn gas engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sub-chamber structure of a lean fuel gas engine in which combustion gas is ejected from a sub-chamber along a swirl in a main chamber.

(Conventional technology) Conventionally, a lean combustion gas engine has a sub-chamber provided above a main chamber. The fuel gas injected from a fuel nozzle into the sub-chamber is added by an addition plug to perform primary combustion, and this combustion gas is discharged. An injection hole opened at the lower part of the sub-chamber is configured to inject into the main chamber to burn a lean mixture in the main chamber.

(Problems to be Solved by the Invention) In the above-described conventional lean-burn gas engine, when a lean air-fuel mixture is sucked into the main chamber, a swirl b is generated in the main chamber a as shown in FIG. It is like,
The combustion gas d injected into the main chamber a from the sub chamber c is in a direction orthogonal to the swirling direction of the swirl b (radial direction of the swirl).
Therefore, swirl b and combustion gas d interfere and swirl b
And the combustion efficiency in the main chamber a decreased, and the NOx in the gas increased.

The present invention has been made with a view to improving the above-mentioned disadvantages, and aims to provide a sub-chamber structure of a lean burn gas engine in which NOx in exhaust gas is reduced by improving combustion efficiency in a main chamber. is there.

(Means and Actions for Solving the Problems) In order to achieve the above object, the present invention is directed to an injection hole opened at a lower portion of a sub-chamber with a combustion gas burned in a sub-chamber. In the lean burn gas engine in which the lean mixture is burned into the main chamber by injecting the lean mixture into the main chamber, the swirl of the lean mixture in which the fuel gas is injected into the main chamber in advance is provided. From the radial direction to the turning direction.

As a result, the combustion gas injected from the sub chamber into the main chamber and the swirl due to the lean mixture in the main chamber do not interfere with each other, so that the combustion efficiency can be improved and NOx in the exhaust gas can be reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the inclination angle of the injection hole is set in a range of 20 degrees to 30 degrees.

This provides the best match for the swirl in the main room.

(Embodiment) An embodiment of the present invention will be described in detail with reference to the drawings shown in FIGS.

In FIG. 1, reference numeral 1 denotes a cylinder lock in which a plurality of (only one is shown in the figure) cylinders 1a are formed,
The piston 2 is housed in the cylinder 1a, and the upper part of the cylinder 1a is the main chamber 3.

Reference numeral 4 denotes a cylinder head mounted on the cylinder lock 1. The cylinder head 4 has a suction port 4 a for sucking a lean air-fuel mixture into the main chamber 3 and an exhaust port 4 a for discharging exhaust gas.
An exhaust port 4b for discharging air from the inside is provided for each cylinder 1a, and an intake valve 5 and an exhaust valve 6 are provided at openings of the intake port 4a and the exhaust port 4b on the main chamber 3 side, respectively.

Reference numeral 7 denotes a sub-chamber assembly mounted in the cylinder head 4 so as to be located at the center of the main chamber 3, and includes a nozzle 7b having a sub-chamber 7a formed therein and a holder screwed to the nozzle 7b.
A plug 8 is provided in the holder 7c to ignite the fuel gas ejected from the fuel nozzle (not shown) into the sub-chamber 7a through the sub-chamber fuel supply passage 7d.

On the other hand, the nozzle 7b constituting the sub-chamber assembly 7 has a plurality of injection holes 7e opened in the main chamber 3 in the lower part as shown in FIG.

These injection holes 7e are formed at an angle of, for example, 45 ° with respect to the horizontal plane, and swirl 9 generated in advance in the main chamber 3 (the intake port 4a when a lean mixture is sucked into the main chamber).
So that the combustion gas can be injected along the turning direction of the intentionally generated one (see FIG. 4).
As shown in FIG. 3, the swirl 9 is inclined at an angle α of 20 ° to 30 ° in the turning direction from the radial direction of the swirl 9.

Next, the operation will be described. The sub-chamber fuel gas ejected from a fuel nozzle (not shown) reaches the sub-chamber 7a via the sub-chamber fuel supply passage 7d, and is ignited by the spark plug 8 in the sub-chamber 7a to perform primary combustion. I do.

This combustion gas is injected into an injection hole 7e opened at the lower part of the sub chamber 7a.
The injection holes 7e are swirled 9 generated in advance in the main chamber 3 (intentionally induced by the intake port 4a when a lean air-fuel mixture is sucked into the main chamber 3). The combustion gas ejected from the injection hole 7e along the swirl 9 in the main chamber 3 as shown in FIG. It is gushing.

As a result, the swirl 9 of the combustion gas and the lean air-fuel mixture are mixed without interfering with each other, and the lean air-fuel mixture in the main chamber 3 is burned with high efficiency, so that the combustion efficiency can be improved and the NOx in the exhaust gas can be reduced. Become like

FIG. 5 is a diagram showing data obtained when an experiment was conducted while changing the angle α of the injection hole 7e.

In this figure, the curve with a circle represents α = 0 °, and the curve with a triangle represents α = 25.
° indicates

(Effects of the Invention) As described in detail above, the present invention inclines the injection holes for injecting the combustion gas from the sub chamber to the main chamber in advance in the swirl direction of the lean mixture generated in the main chamber. The combustion gas can be ejected from the sub-chamber along the swirl in the room.

As a result, the swirl at the time of combustion in the main chamber is further strengthened, so that the lean mixture can be stabilized and burned, and the swirl and the combustion gas of the lean mixture do not interfere with each other as in the conventional case. The lean mixture can be burned with high efficiency, and the combustion efficiency can be improved.

In addition, NOx in exhaust gas can be reduced by improving combustion efficiency.

Further, by setting the inclination angle of the injection hole to 20 to 30 degrees, the one that is most suitable for the swirl of the main chamber can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lean burn gas engine according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a sub-chamber, and FIG.
FIG. 4 is a view illustrating the operation, FIG. 5 is a diagram illustrating the experimental results, and FIG. 6 is a conventional view. 3… Main room, 7a… Sub room 7e… Injection hole, 9… Swirl

Claims (2)

(57) [Scope of request for utility model registration] A combustion gas which has been subjected to primary combustion in a sub-chamber (7a) is injected into a main chamber (3) from an injection hole (7e) opened at a lower portion of the sub-chamber (7a). In the lean burn gas engine configured to burn the lean mixture in (3), the injection hole (7e) for injecting the combustion gas into the main chamber (3) is generated in advance in the main chamber (3). Swirl of lean mixture (9)
Sub-chamber structure of a lean burn gas engine which is inclined at an angle (α) from the radial direction to the turning direction. 2. The sub-chamber structure of a lean burn gas engine according to claim 1, wherein the inclination angle (α) of the injection hole (7e) is in the range of 20 ° to 30 °.