JPS59119012A - Combustion chamber of auxiliary combustion chamber type engine - Google Patents

Abstract

PURPOSE:To reduce the throttle loss at an auxiliary combustion chamber nozzle and improve the mixing of fuel and air and the burning of the air-fuel mixture by a method wherein the axis line of an auxiliary combustion chamber nozzle is formed by a part of a circle, the center of which is at a specified position, in an engine equipped with a main combustion chamber and the auxiliary combustion chamber. CONSTITUTION:The upper structure of an auxiliary combustion chamber 2 is hemispherical, while its lower structure is circular truncated conical. Let the X-axis be in the direction directed to the center of a cylinder at right angle to the center line A-A of the precombustion chamber 2 and the Y-axis be in the direction directed upward from an engine parallel to the center line A-A. The axis line of an auxiliary combustion chamber nozzle 3 is formed by a part of a circle, the position of the center of which has the co-ordinate (X>=0, y>=h) and the radius of which is (r) so as to be able to ensure the proper value of the turning radius rS of the jet J, which flows in the auxiliary combustion chamber 2 during compression stroke. Because the angle theta1 of the auxiliary combustion chamber nozzle 3 is small, the jet penetration in a main combustion chamber 1 is increased, resulting in enabling to enlarge the passage area of the auxiliary combustion chamber nozzle 3. Thus, the lowering of fuel consumption, reduction of exhaust smoke, lowering of noise and the like are contrived.

Description

[Detailed description of the invention] The present invention relates to a combustion chamber of a pre-chamber engine.

Figure 1 shows the subchamber nozzle of a conventional swirl chamber engine.

In the figure, the sub-combustion chamber 2 is recessed within the cylinder head 4. The structure of the auxiliary combustion chamber 2 includes a hemispherical upper part and a truncated conical or cylindrical lower part, and FIG. 1 shows a truncated conical lower part. A fuel injection valve 5 and a glow plug 6 for preheating the inside of the auxiliary combustion chamber 2 at the time of starting the engine are installed in the auxiliary combustion chamber 2 as necessary. The auxiliary combustion chamber 2 is connected to the top surface of the piston shifter 0, the cylinder 8. The air in the combustion chamber 1 is communicated with the main combustion chamber 1 formed from the lower surface of the cylinder head 4 and is compressed, passing through the sub-chamber nozzle 3 to the sub-combustion chamber 2.
The vortex flow S is generated. When fuel is injected through the fuel injection valve 5 along the direction of the vortex a, the fuel swirls in the sub-combustion chamber 2 together with the vortex S.

Fuel and air are mixed, ignited, and burned. The unburnt fuel ejected from the sub-combustion chamber 2 is mixed with the air within the main combustion chamber 1 by gas ejected from the sub-combustion chamber 2. The jet flow flowing out from the sub-combustion chamber 2 reaches the cylinder wall 8 on the opposite side of the sub-combustion chamber 2 with respect to the cylinder center lines B-, H, and collides with the wall surface. After the collision, the particles are dispersed along the wall surface of the cylinder wall 8.

However, the above method has the following drawbacks.

In order to improve mixture formation and combustion in the main combustion chamber 1, the jet must reach the cylinder wall 8 in a short time.

Generally, in the case of a vortex-type subchamber, it is structurally impossible to install the subchamber closer to the center of the piston due to the arrangement of intake and exhaust valves, etc. Therefore, since the passage area of the sub-chamber nozzle 3 is made small and the jet velocity is increased, the loss of the throttle 9 of the sub-chamber nozzle 3 and the heat loss in the main combustion chamber 1 are large.

As shown in Fig. 2, when the pre-chamber nozzle angle θ is decreased,
Since the jet penetration within the main combustion chamber 1 is increased, the passage area of the sub-chamber nozzle 3 can be increased.

However, if the pre-chamber nozzle angle θ is made small in the conventional sub-chamber nozzle 3 which is linear as shown in Fig. 3, the sub-combustion chamber 2 during the expansion stroke
When gas is ejected from the main combustion chamber 1 to the main combustion chamber 1, the angular difference (
Since 180-θ)0 becomes large, it becomes difficult for gas to flow out into the main combustion chamber 1, and the pre-chamber injection throttling loss becomes large.

The purpose of the present invention is to focus on the above points, and to reduce the throttling loss of the sub-chamber nozzle and improve the mixing and combustion of fuel and air in the main combustion chamber. The objective is to provide a shape of the pre-chamber nozzle that facilitates outflow and improves jet flow penetration within the main combustion chamber.The feature is that the origin is set at the opening end of the main combustion chamber side of the axis of the pre-chamber nozzle. 9. The y-axis is perpendicular to the center line of the auxiliary combustion chamber and the positive direction is toward the cylinder center. If we take the y-axis parallel to the center of the auxiliary combustion chamber and the positive direction is above the engine, then X≧0
．． The axis of the subchamber nozzle is formed by a part of a circle having a center at a position where y≧0.

The present invention is applicable to subchamber type internal combustion engines in general.

Embodiments of the present invention will be described below with reference to the drawings.

In Fig. 4, the origin is the point at the opening end of the axis of the sub-chamber nozzle 3 on the main combustion chamber 1 side, and the y-axis is drawn in the direction of the cylinder center at right angles to the center of the sub-combustion chamber [A-A (positive direction)]. , the y-axis is taken above the engine parallel to the center line A-A of the sub-combustion chamber (
positive direction). The axis of the sub-chamber nozzle 3 is formed by a part of a circle having a radius r and having its center at a position where X≧o, y>O.

The thickness h of the sub-chamber cap 9 is defined as the distance from the origin to the bottom of the sub-combustion chamber 2. In addition, the axis of the main combustion chamber 1 of the pre-chamber nozzle 3
If the outflow angle at the side opening end with respect to a plane perpendicular to the centerline A-A of the subcombustion chamber is 01, and the outflow angle of the coaxial line at the subcombustion chamber 2 side opening end is θ2, the following equation holds true.

x = r cos , (90-θt)' (1)
y = r, sin (90-θt)' (2) y
-h = -r, sin (90-θ2) (3
) In formula (1), since X≧0, 0 × θ1 × 18
0° (see Figure 5) A graph of 2 equations (2) t (3): 6; Figures 6 and 7 show the radius r of the circle and the thickness h of the sub-chamber cap 9. Depending on the relationship, the graph will be different.

Figure 6 shows the case where r>h, and since 0 x y x r, θ1
<θ2.0 x θ1 x 90°. Also, at 0 x y x h, it is 90° x θz x 180°.

When h<y≧r, θ2 is 90°. Figure 7 shows r (
In the case of h, +h−r×y<, r.

θ1〈θ2,0 θ1 90°, 90° θ2 180
It is 0.

To summarize the above, when X≧0+y≧0, θ1 decreases θ2,0
When θ1 is 90°, 0, y, and h is 90° and θ2 is 180°, and when y>h, θ2 is 90°.

A first embodiment according to the present invention is shown in FIGS. 8 and 9. The upper structure of the sub-combustion chamber 2 is hemispherical, the lower part is a truncated cone (there is also a cylindrical shape, but a truncated cone is shown), and the sub-chamber nozzle With the point at the opening end of the main combustion chamber 1 side of the axis of No. 3 as the origin, the y-axis is perpendicular to the auxiliary combustion chamber center line A-A in the direction of the cylinder center (positive direction), and the auxiliary combustion chamber center line A - If the y-axis is taken parallel to A and above the engine (positive direction), the axis of the pre-chamber nozzle 3 is x 〉
FIGS. 8 and 9 show an arc-shaped subchamber nozzle formed by a part of a circle with a radius r and having a center at a position where O'# y≧h.

FIG. 8 shows the case where the opening of the sub-chamber nozzle 3 on the sub-combustion chamber 2 side includes the sub-combustion chamber center line A-A as the position of the sub-chamber nozzle 3, and FIG. This is the case where the cylinder center line B'-B is on the opposite side to the chamber center line A-A.

In this case, the angles θ1 and θ2 of the subchamber nozzle 3 are θ1
θ2 , θ1 , θ2 90°.

The functions and effects of the above configuration will be described.

By using the above-mentioned auxiliary chamber nozzle 3, the turning radius r8 of the jet flow J of the gas in the main combustion chamber 1 into the auxiliary combustion chamber 2 caused by the compression of the gas in the main combustion chamber 1 by the piston 7 during the compression stroke can be reduced. An appropriate value can be maintained, and the mixing and combustion of fuel and air in the sub-combustion chamber 2 can be improved.

In addition, since the angle θ2 of the sub-chamber nozzle 3 is large, gas can be easily ejected from the sub-combustion chamber 2 to the main combustion chamber 1 during the expansion stroke, and furthermore, since the angle θ1 of the sub-chamber nozzle 3 is small, the main The penetration of the jet within the combustion chamber 1 is increased, and the mixing and combustion of unburned fuel and air is promoted, so that the passage area of the pre-chamber nozzle 3 can be expanded.

In addition, since the axis of the subchamber nozzle 3 is composed of a part of a circle,
Since the angle of the subchamber nozzle 3 changes continuously from 01 to θ2, the flow resistance within the subchamber nozzle 3 becomes small.

Therefore, it is possible to reduce the throttling loss at the pre-chamber nozzle 3 and the heat loss in the main combustion chamber 1, improving fuel efficiency and smoke emissions, as well as realizing lower noise, higher speed, and improved startability of the engine. can.

FIG. 10 is a sectional view showing a combustion chamber of a second embodiment of the present invention.

In the first embodiment, the axis of the subchamber nozzle 3 is formed of a part of a piece of meat having a radius r and having a center at a position where X>0° circle 0 <y < h.

In this case, the angle θ1 of the subchamber nozzle 3.

θ2 is θ1〈θ2, 0 θl 90°, 90 θ2 1
It becomes 80°.

By using the sub-chamber nozzle 3 as described above, the turning radius r8 of the jet J into the sub-combustion chamber 2 during the compression stroke can be ensured at an appropriate value.

In addition, the position of the sub-chamber nozzle 3 can be moved closer to the cylinder center line B-B without changing the structure of the sub-chamber cap 9, and the ejected gas energy required for mixing fuel and air in the main combustion chamber 1 can be reduced. can be reduced. Furthermore, the angle θ1 of the subchamber nozzle 3 is small.

Because the jet penetration inside the main combustion chamber 1 increases.

The passage area of the subchamber nozzle 3 can be expanded.

Therefore, low fuel consumption, low smoke emissions, low noise, etc. can be achieved.

FIG. 11 is a sectional view showing a combustion chamber of a third embodiment according to the present invention.

In this case, in the first embodiment, the auxiliary combustion chamber center line A-
A is inclined with respect to the cylinder center line B-, H, and its operation and effect are the same as in the first embodiment.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a combustion chamber with a conventional pre-chamber nozzle, Figure 2 is a diagram showing the angle of the first pre-chamber nozzle and jet penetration in the main combustion chamber, and Figure 3 is a diagram showing the angle of the first pre-chamber nozzle and the jet penetration in the main combustion chamber. FIG. 4 is an explanatory view showing the state of gas flowing out into the main combustion chamber, and FIG. 4 is an explanatory view showing the relationship between the axis of the sub-chamber nozzle and the circle r forming the axis in the embodiment of the present invention. Figure 5 is a diagram showing the relationship between the circle r and the outflow angle θl at the opening end of the sub-chamber nozzle on the main combustion chamber side, and Figures 6 and 7 are diagrams showing the relationship between the outflow angle θ1 at the opening end on the main combustion chamber side and the sub-combustion A line diagram showing the relationship between the chamber side opening end and the outflow angle θ2, FIGS. 8 and 9 are respectively sectional views showing a combustion chamber provided with a sub-chamber nozzle according to the first embodiment of the present invention, and FIG. FIG. 11 is a sectional view showing a combustion chamber provided with a pre-chamber nozzle according to a second embodiment of the present invention, and FIG. 11 is a sectional view showing a combustion chamber provided with a pre-chamber nozzle according to a third embodiment of the present invention. 1... Main combustion chamber, 2... Sub-combustion chamber, 3... Sub-chamber nozzle. A-A...Sub-combustion chamber center line, B-B...Cylinder center line O Fig. 1-11 Sub-chamber nozzle again θ. 21 73 Figure 74 Figure θ1 75 Deo 6j θ 7101￥1 71st Genryo Motor Co., Ltd. Kyoto Works 0 Author: Isao Nakanishi - 0 Author: Mitsubishi Motors Corporation, Ichibanchi, Uzumasa Tatsumi-cho, Ukyo-ku, Kyoto City Company within Kyoto Works ■Applicant: Mitsubishi Motors Corporation 5, Shiba, Minato-ku, Tokyo
Chome 33-8

Claims (1)

[Claims] 1. An injection port in the sub-chamber that communicates the main combustion chamber with the sub-combustion chamber;
If we take the y-axis parallel to the center line of the auxiliary combustion chamber and the positive direction is above the engine. X≧0. A combustion chamber for a pre-chamber engine, characterized in that the axis of the pre-chamber nozzle is formed by a part of a circle having a center at a position where y≧0.