JPH0610415B2 - Subchamber engine combustion chamber - Google Patents

Description

The present invention relates to a combustion chamber of an auxiliary chamber type engine.

[Prior Art] FIG. 7 shows a combustion chamber of a conventional auxiliary chamber engine.

The auxiliary combustion chamber 2 is recessed in the cylinder head 4, and the auxiliary combustion chamber 2 may have a hemispherical upper part and a truncated cone or lower columnar shape. Shows the thing. A fuel injection valve 5 and a glow plug 6 for preheating the inside of the auxiliary combustion chamber 2 when starting the engine are installed in the auxiliary combustion chamber 2 as required. The sub-combustion chamber 2 communicates with the main combustion chamber 1, which is constituted by the top surface of the piston 7, the cylinder 8 and the lower surface of the cylinder head 4, via the sub-chamber injection port 3. The passage area of the auxiliary chamber nozzle 3 is constant.

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

Air in the main combustion chamber 1 is compressed by the piston 7 in the compression stroke during engine operation, flows into the auxiliary combustion chamber 2 through the auxiliary chamber injection port 3, and a swirl S is generated. When fuel is injected from the fuel injection valve 5 along the direction of the vortex S, the fuel is circulated in the auxiliary combustion chamber 2 together with the vortex S, and the fuel and air are mixed and ignited and burned. Combustion gas and unburned fuel in the sub combustion chamber 2 are ejected into the main combustion chamber 1 through the sub chamber injection port 3, work on the piston 7, and at the same time perform mixed combustion with air in the main combustion chamber 1. Close. That is, the jet flowing out from the sub combustion chamber 2 reaches the cylinder wall 8 on the side opposite to the sub combustion chamber 2 with respect to the cylinder center line BB, collides with the wall surface, and after the collision, along the wall surface of the cylinder wall 8. Spread.

[Problems to be solved by the invention]

However, in order to improve combustion in the sub-chamber engine, it is important to form a mixture of fuel and air in the sub-combustion chamber 2 and the main combustion chamber 1 and promote combustion. For this reason, the passage area of the auxiliary chamber injection port 3 is reduced and the jet velocity is increased. When the passage area of the auxiliary chamber injection port 3 is reduced, the jet velocity into the auxiliary combustion chamber 2 and accordingly the vortex velocity are increased, and the formation and combustion of the air-fuel mixture in the auxiliary combustion chamber 2 is promoted. On the contrary, it becomes difficult for the combustion gas and the unburned materials to flow out from the auxiliary combustion chamber 2 to the main combustion chamber 1,
As the throttle loss of the auxiliary chamber injection port 3 increases, the auxiliary combustion chamber 2
Insufficient air inside, combustion delay in the main combustion chamber 1 and combustion failure occur, resulting in deterioration of fuel efficiency and smoke emission. This phenomenon is caused by the auxiliary combustion chamber 2
It becomes more noticeable as the internal combustion becomes more active and the sub-chamber pressure becomes higher.

The object of the present invention is to eliminate the drawbacks of the above-mentioned conventional device, increase the vortex flow S in the auxiliary combustion chamber, facilitate the outflow of gas from the auxiliary combustion chamber to the main combustion chamber, and improve the fuel in the auxiliary combustion chamber and the main combustion chamber. It is to provide a combustion chamber for a sub-chamber engine that can improve the mixing and combustion of air.

[Means for solving problems]

Inside the sub-chamber base 9 is adjacent to the sub-chamber injection port 3, and the sub-combustion chamber 2
Further, communication holes 12 and 13 communicating with the main combustion chamber 1 and a cavity 11 opening in the sub-chamber nozzle passage wall are provided, and a sub-chamber nozzle control member 14 is built in the cavity 11.
The sub-chamber control member 14 has pressure-receiving portions 15 so that the sub-chamber control members 14 are moved into the space 11 by the main and sub-chamber pressures p ₁ and p ₂ during engine operation, and the pressure-receiving areas F are formed to be substantially the same. Has been done. Further, when the control member 14 comes closest to the sub chamber nozzle 3, the end of the control member 14 on the side of the sub chamber nozzle always projects into the sub chamber nozzle 3. In addition, a stopper 16 for limiting the operation range of the auxiliary chamber injection port control unit 14 is provided in the space 11.
Is provided.

[Action]

When the variable area sub-chamber nozzle 3 of the present invention is used, (P ₁ −p ₂ ) F> 0 during the compression stroke, so the sub-chamber nozzle control member 1
No. 4 is pushed into the auxiliary chamber injection port, the passage area is reduced, and the vortex flow in the auxiliary combustion chamber 2 is strengthened. Also during the expansion stroke,
(P ₁ −p ₂ ) F> 0 and the sub chamber injection port control member 14 is pushed into the mouthpiece 9 to increase the sub chamber injection port passage area, which facilitates gas outflow from the sub combustion chamber 2 into the main combustion chamber 1. At the same time, the gas flow loss at the sub chamber injection port 3 is reduced.

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

(1) First Embodiment FIG. 1 is a sectional view of the combustion chamber of the first embodiment, FIG. 2 is a view taken along the line CC of FIG. 1, and FIG. 3 is a view taken along the line DD. Fig. 4
(a) is an explanatory view of the operation in the case of p ₁ > p ₂ and FIG. 4 (b) is the case of p ₁ <p _2. The lower part of FIG. 5 shows the main and auxiliary chamber pressures p ₁ , p ₂ and the crank angle θ. A relational diagram, the upper part of FIG. 5, is a relational diagram between the auxiliary chamber injection passage area f and the crank angle.

The sub combustion chamber 2 is recessed in the cylinder head 4. The shape of the sub-combustion chamber 2 is hemispherical at the upper part, and is frustoconical at the lower part,
Alternatively, there is a cylindrical shape, but FIG. 1 shows a lower part having a truncated cone shape. A fuel injection valve 5 and a glow plug 6 for preheating the inside of the auxiliary combustion chamber 2 when the engine is started are installed in the auxiliary combustion chamber 2 as required. The sub combustion chamber 2 is connected to the top surface of the piston 7, the cylinder 8 and the cylinder head 4 through the sub chamber injection port 3.
Communicates with the main combustion chamber 1 composed of the lower surface of

Inside the sub-chamber base 9 is adjacent to the sub-chamber injection port 3, and the sub-combustion chamber 2
Further, the communication holes 12 and 13 communicating with the main combustion chamber 1 and the cavity 11 opening in the sub-chamber nozzle passage wall are provided, and the sub-chamber nozzle control member 14 is built in the cavity 11.
The sub chamber injection port control member 14 is provided with a pressure receiving portion 15 so that it can be moved in the space 11 by the pressures p ₁ and p ₂ of the main and sub chambers during engine operation. Is formed in. Further, when the control member 14 is pushed toward the sub chamber injection port 3, the end of the sub chamber injection port of the control member 14 always projects into the sub chamber injection port 3. Further, a stopper 16 for limiting the operation range of the sub chamber injection port control member 14 is provided in the space 11.

As the shape of the sub chamber injection port control member 14, a combination of flat plates is shown in FIG. 1, but a combination of a deformed round bar (having upper and lower flat portions) and a flat plate may be considered. Further, although the pressure receiving portion 15 is shown as having a surface perpendicular to the movement direction of the sub chamber injection port control member 14, it does not necessarily have to be a right angle. As the shape of the end face of the sub chamber injection port control member 14 on the side of the sub chamber injection port, a sharp edge shape having a surface parallel to the wall surface of the sub chamber injection port is shown in FIG. 1, but it does not necessarily have to be parallel. Further, the tip shape may be a semicircle or a combination of a straight line and an arc. C-
The lateral width W of the auxiliary chamber injection port control member 14 in the view of the arrow C is smaller than the auxiliary chamber injection port width a, but W≈a shown in FIG. Further, although the sub-chamber nozzle shape in the D-D arrow view is almost rectangular, an oval shape (a combination of a semicircle and a square shape), an elliptical shape, a circular shape, and the like are also conceivable. Also, the communication hole 12,
As the shape of 13 viewed from the arrow D-D, a circular shape or a plurality of circular shapes can be considered in addition to the rectangular shape shown in FIG.

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

When the variable sub-chamber nozzle 3 according to the present invention is equipped and the main chamber pressure is p ₁ and the sub-chamber pressure is p ₂ , the gas in the main combustion chamber 1 is first compressed in the compression stroke, so p ₁ > p ₂ Therefore, as shown in FIG. 4 (a), the sub chamber injection port control member 14 moves in the direction of the sub chamber injection port 3 by the force of the product (p ₁ −p ₂ ) F of the differential pressure p ₁ −p ₂ and the pressure receiving area F. It moves by being pressed by and the area of the sub-chamber nozzle passage becomes as small as f _c . Therefore, the inflow velocity of the gas in the main combustion chamber 1 into the auxiliary combustion chamber 2 becomes high, the swirl velocity in the auxiliary combustion chamber 2 is strengthened, and the formation and combustion of the air-fuel mixture in the auxiliary combustion chamber 2 is promoted. It Next, in the expansion stroke, if the sub-chamber force accompanying the lowering of the piston 7 is p ₂ , the main chamber pressure is p ₁ , and the pressure receiving area is f, then p ₂ > p _{1 and the} sub-chamber nozzle control member 14 is not affected. It is pressed by the force of (p ₂ −p ₁ ) f toward the sub chamber injection port side, the injection port control member 14 is pushed into the injection port metal 9, and the sub chamber injection port passage area is f _e as shown in FIG. 4 (b). And grows. Therefore, the combustion gas and unburned fuel in the sub-combustion chamber 2 easily flow into the main combustion chamber 1, and the throttling loss of the sub-chamber injection port 3 can be reduced. Formation and combustion of a mixture of fuel and air in the chamber 1 are promoted.

Changes in the main and auxiliary chamber pressures p ₁ and p ₂ and the auxiliary chamber passage area f with respect to the crank angle θ are shown in FIG.

(2) Second Embodiment Unlike the same mechanism of the first embodiment, the variable area type sub-chamber nozzle mechanisms 11 and 14 of the second embodiment are installed on the nozzle passage wall on the opposite side of the sub-chamber nozzle 3. However, the function and effect are almost the same as those of the first embodiment.

(3) Third Embodiment In the third embodiment, a variable area type sub-chamber nozzle mechanism including a sub-chamber inner cavity 11 and a sub-chamber nozzle control member 14 is installed on both sides of the sub-chamber nozzle passage wall. Although this is a form in which the first and second embodiments are combined, the operation and effect thereof are almost the same as those of the first embodiment. However, since there are a plurality of sub chamber ejection port mechanisms, the displacement of each sub chamber ejection port control member 14 can be made small.

〔The invention's effect〕

Since the present invention is configured as described above, at the time of compression, the nozzle flow passage area is reduced, the gas velocity in the nozzle is increased, the vortex in the auxiliary combustion chamber becomes strong, and the mixture of fuel and air in the auxiliary combustion chamber is increased. Formation and combustion are promoted. Also, in the next expansion stroke when the pressure in the sub chamber rises, the area of the nozzle flow passage is expanded, and combustion gas and unburned fuel easily flow out from the sub combustion chamber to the main combustion chamber. The heat loss in the room can be reduced. Also, to prevent deterioration of combustion due to lack of air in the sub-combustion chamber, to promote mixing of air and unburned fuel in the main combustion chamber, and combustion, to improve fuel efficiency and smoke emission of the engine and to increase speed. You can

[Brief description of drawings]

1 to 5 show a first embodiment of the present invention, FIG. 1 is a longitudinal sectional view around a combustion chamber, FIG. 2 is a view taken along the line CC in FIG. 1, and FIG. 3 is D in FIG. -D arrow view, FIG. 4 is an operation explanatory view of the first embodiment, the lower part of FIG. 5 is a relationship diagram of the crank angle θ and the main and auxiliary chamber pressures p ₁ and p ₂ , and the upper part of FIG. 5 is the crank. Angle θ
And FIG. 6 is a diagram corresponding to FIG. 1 of the second embodiment, and FIG. 7 is a diagram corresponding to FIG. 1 of the conventional example. 1 ... Main combustion chamber, 2 ... Sub combustion chamber, 3 ... Sub chamber injection port, 9
…… Sub-chamber base, 11 …… Vacancy, 12 …… First contact hole,
13 ... Second communication hole, 14 ... Sub chamber injection port control member, P
_{1 ......} main combustion chamber pressure, p 2 _...... auxiliary combustion chamber pressure, f ...
… The nozzle area.

Claims (1)

[Claims] 1. A sub-chamber type diesel engine having a sub-combustion nozzle for communicating the sub-combustion chamber with the main combustion chamber in the sub-chamber mouthpiece,
A void opening to the auxiliary chamber injection port, a first communication hole that communicates the void and the auxiliary combustion chamber, a second communication hole that communicates the void and the main combustion chamber, and the interior of the void. And is reciprocally slidably provided in the sub-combustion chamber due to the difference between the pressure in the sub-combustion chamber introduced from the first communication hole and the pressure in the main combustion chamber introduced from the second communication hole. And a sub-chamber nozzle control member for changing the area of the jet nozzle.