JPH04117148U - Combustion chamber of pre-chamber internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] Improve fuel-air mixture formation and combustion in the sub-combustion chamber, promote gas flow from the sub-combustion chamber to the main combustion chamber, and improve fuel efficiency, smoke emissions, and _NOx. We aim to reduce the [Structure] The auxiliary combustion chamber consists of an upper part of the auxiliary combustion chamber made up of a combination of a hemisphere, a cylinder, and a right circular cone, and a lower part of the auxiliary combustion chamber made up of a combination of a cylinder and a hemisphere.The auxiliary combustion chamber is installed in or near the center of the cylinder. It has a plurality of auxiliary chamber nozzles at its tip. The lower centerline C-C of the sub-combustion chamber is in line with the cylinder centerline B-B with respect to the upper centerline A-A of the sub-combustion chamber.
A fuel injection valve that injects fuel in the downstream direction of the vortex S generated within the combustion chamber is provided at the upper end of the sub-combustion chamber.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

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

0002

[Conventional technology]

Figure 3 shows the combustion chamber of a conventional sub-combustion chamber. The auxiliary combustion chamber 2 is installed inside the cylinder head 4. The shape of the kerat is basically cylindrical, and the center line of the sub-combustion chamber shape is A-A. It is only. The auxiliary combustion chamber 2 contains a fuel injection valve 5 and auxiliary combustion as needed when starting the engine. A glow plug (not shown) is provided to preheat the inside of the baking chamber 2. The auxiliary combustion chamber 2 is connected to the top surface of the piston 6, the cylinder liner 7, and the cylinder via the auxiliary chamber nozzle 3. It communicates with a main combustion chamber 1 consisting of a combustion chamber head 4 via a sub-chamber nozzle 3.

0003 Next, the operation of the conventional example will be explained. When the air in the cylinder is compressed by the piston 6 during the compression stroke during engine operation. , flows into the sub-combustion chamber 2 through the sub-chamber nozzle 3. At the end of the compression stroke, the When fuel is injected into compressed air from the fuel injection valve 5, the fuel and air mix and ignite. Burn. The unburnt fuel that ignites and burns in this auxiliary combustion chamber and rises in pressure enters the main combustion chamber 1. The structure is such that the air is ejected and mixed with the air in the main combustion chamber, resulting in good combustion. .

0004

[Problem that the idea aims to solve]

However, in the combustion chamber of the conventional auxiliary chamber type engine shown in Fig. 3, the main combustion Although gas outflow into chamber 1 is promoted, the gas flow (vortex) in sub-combustion chamber 2 is mostly As a result, the mixture of fuel and air is not formed sufficiently. Therefore, the energy of the gas ejected into the main combustion chamber is insufficient, so unburned fuel remains in the main combustion chamber 1. This results in poor mixture formation and combustion between the fuel and air, resulting in poor fuel efficiency and smoke emissions. prevent this Therefore, by narrowing the passage area of the pre-chamber nozzle and increasing the gas outflow speed to the main combustion chamber 1 , smoke emission during high loads is improved, but it becomes difficult for gas to flow into the main combustion chamber 1, and the auxiliary chamber Nozzle throttling loss increases and fuel efficiency deteriorates. Also, when the load is low, fuel flows inside the main combustion chamber 1. Too much dispersion results in poor combustion and worsens smoke emissions.

[0005] The purpose of the present invention is to solve the problems of the conventional device mentioned above, and to improve the mixing of fuel and air in the auxiliary combustion chamber. Reduces gas outflow from the secondary combustion chamber to the main combustion chamber by improving aeration formation and combustion. The purpose of the present invention is to provide a combustion chamber for an auxiliary internal combustion engine that promotes fuel efficiency and reduces smoke emissions.

[0006]

[Means to solve the problem]

The combustion chamber of the subchamber type internal combustion engine of the present invention is such that the subcombustion chamber is located at or near the center of the cylinder. and further has a plurality of sub-chamber nozzles, the sub-combustion chamber is hemispherical The upper part of the auxiliary combustion chamber consists of a combination of shapes, cylinders, and right circular cones, and the combination of cylinders and hemispheres. and a lower part of the sub-combustion chamber, and the center line C-C of the lower part of the sub-combustion chamber is It is inclined toward the side opposite to the cylinder center line with respect to the upper center line A-A of the sub-combustion chamber, and the engine The upper end of the auxiliary combustion chamber is configured to generate a vortex S in the auxiliary combustion chamber during the compression stroke of the auxiliary combustion chamber. The fuel injection valve disposed at is installed so as to inject fuel in the downstream direction of the vortex Further, in claim 2, the inclination angle θ of the ridgeline of the right circular cone portion is 45°≦θ≦65°. It is characterized by being within the range.

[0007]

[Effect]

During the compression stroke, air pushed out by the piston flows from the main combustion chamber into the auxiliary combustion chamber. In this case, the center line C-C of the lower part of the sub-combustion chamber is located at the center of the cylinder relative to the center line A-A of the upper part of the sub-combustion chamber. It is inclined in the opposite direction to the line, and the upper part 21 of the sub-combustion chamber is a combination of a cylinder and a hemisphere. As a result, a vortex S is generated within the sub-combustion chamber. In addition, the lower part 22 of the sub-combustion chamber is thin. Because it has a cylindrical shape, gas diffusion is small and the vortex velocity in the upper part 21 of the sub-combustion chamber is reduced. You can make it bigger. Furthermore, fuel from the fuel injection valve 5 is injected toward the downstream of the vortex. Together with this, the formation of a mixture of fuel and air, and therefore combustion, is promoted.

[0008] In addition, since the bottom of the upper part 21 of the sub-combustion chamber is configured in a right circular conical shape, during the expansion stroke The burned and unburned gases in the upper part 21 of the auxiliary combustion chamber quickly flow out into the main combustion chamber 1. Especially the above The effect is great when the inclination angle θ is 45°≦θ≦65°. Substitutes such as above Mixing of fuel and air in the main combustion chamber 1 by promoting combustion in the combustion chamber 2, and therefore combustion In addition, since the sub-combustion chamber 2 is installed in the center of the cylinder, the sub-chamber injection Even if the mouth passage area is expanded, combustion can be ensured within the sub-combustion chamber 2 and the main combustion chamber 1, so Throttle loss at the sub-chamber nozzle 3 and heat loss within the main and sub-combustion chambers can be reduced.

[0009]

【Example】

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a first embodiment, in which a sub-combustion chamber 2 is provided in a cylinder head 4, and a sub-chamber injection It is formed from the top surface of the piston 6, the cylinder 7, and the bottom surface of the cylinder head 4 through the port 3. It communicates with the main combustion chamber 1. Also, the auxiliary combustion chamber 2 is located on the cylinder center line B-B or It is composed of an upper part 21 and a lower part 22 of the auxiliary combustion chamber, which are located close to it. . A plurality of auxiliary chamber nozzles 3 are provided at the tip of the auxiliary combustion chamber lower part 22 on the side of the main combustion chamber, and the nozzles 3 are The tip of the auxiliary combustion chamber is provided to protrude into the main combustion chamber. Also, in the auxiliary combustion chamber 2 A glow plug (not shown) is installed to preheat the chamber as necessary when starting the engine. It will be done.

0010 The upper part 21 of the auxiliary combustion chamber is composed of a combination of a hemisphere, a cylinder, and a right circular cone, and the lower part of the auxiliary combustion chamber The part 22 is composed of a cylinder or a combination of a cylinder and a hemisphere, and further includes a sub-combustion chamber. The lower center line C-C is the cylinder center line B-B with respect to the upper center line A-A of the auxiliary combustion chamber. Since it is inclined to the opposite side, a vortex S is generated in the sub-combustion chamber 2. Also, fuel injection An injection valve 5 is installed at the upper end of the upper part 21 of the auxiliary combustion chamber, and injects fuel toward the downstream direction of the vortex S. is being injected.

[0011] Next, the operation of the above embodiment will be explained. When the engine is running, the air inside the cylinder pushed up by the piston 6 during the compression stroke is It flows into the sub-combustion chamber 2 from the chamber nozzle 3 . However, the center line C- of the lower part 22 of the auxiliary combustion chamber C is the direction opposite to the cylinder center line B-B with respect to the center line A-A of the upper part 21 of the sub-combustion chamber. At the same time, the upper part of the sub-combustion chamber 2 is a combination of hemispherical and cylindrical shapes, creating a vortex. A stream S is generated. In addition, since the lower part 22 of the sub-combustion chamber is cylindrical, there is less gas diffusion, and the upper part of the sub-combustion chamber The vortex S of can be strengthened. Furthermore, the fuel spray from the fuel injection valve 5 flows into a vortex. Combined with the injection in the downstream direction of S, the mixing of fuel and air, and therefore combustion, is promoted. be done.

0012 In addition, since the bottom surface of the upper part 21 of the auxiliary combustion chamber is configured in a right circular conical shape, the auxiliary combustion chamber is Gas flows out smoothly from the combustion chamber 2 to the main combustion chamber 1, and the combustion inside the main combustion chamber 1 is improved. Mixing of fuel and air and therefore combustion is promoted. In addition to the above actions and effects, the secondary combustion chamber 2 Since it is installed on the axis of the cylinder or near its center line, the diameter of the subchamber nozzle 3 can be Even if the size is increased, combustion is ensured in the sub-combustion chamber 2 and main combustion chamber 1, and the throttle at the sub-chamber nozzle 3 is It is possible to reduce heat loss in the main and sub-combustion chambers.

[0013] Next, a second embodiment will be explained. As shown in FIG. The angle θ between the plane perpendicular to the upper center line A-A of the sub-combustion chamber and the ridgeline of the right circular cone is 45. The configuration is such that °≦θ≦65°.

[0014] Next, the operation of the second embodiment will be explained. As shown in Fig. 2, if the inclination angle θ is 45°≦θ≦65°, the fuel consumption will increase even in the low load range. Both fuel consumption and smoke emissions are good, but when θ is outside the above range, the fuel consumption and smoke emissions are low. Getting worse. The cause is the vortex generation ability in the sub-combustion chamber, and the adhesion of fuel to the right circular cone. , associated with the gas outflow into the main combustion chamber 1. That is, when the inclination angle θ is smaller than the appropriate range, the vortex decelerates quickly. The vortex velocity decreases, the distance from the fuel injector to the right circular cone becomes shorter, and the right circular cone Since the amount of fuel adhering to the wall increases, combustion within the sub-combustion chamber deteriorates. moreover It becomes difficult for gas to flow out into the main combustion chamber 1, and combustion within the main fuel chamber 1 deteriorates. As a result of the above, fuel efficiency and smoke emissions worsen. Therefore, the minimum value of the inclination angle θ is θ=45° It is.

[0015] Next, when the inclination angle θ is larger than the range, the fuel injection valve The distance at However, the vortex velocity in the sub-combustion chamber decreases (the vortex strength decreases), and the fuel and Air mixing and therefore combustion deteriorate, resulting in poor fuel efficiency and smoke emissions. Especially in low load range Smoke emissions and fuel consumption deteriorate significantly. As mentioned above, at low loads, fuel is burned in the auxiliary combustion chamber 2. Since combustion is not possible, combustion within the main combustion chamber 2 becomes even more difficult. Therefore the slope The upper limit of the angle is θ=65°. As mentioned above, when the inclination angle θ is within the range of 45°≦θ≦65°, The vortex generation ability, fuel adhesion, and gas outflow into the main combustion chamber 1 are improved, and the low load area is improved. Improves fuel efficiency and smoke emissions.

[0016]

[Effect of the idea]

Since the combustion chamber of the auxiliary internal combustion engine of the present invention is configured as described above, it is possible to prevent the generation and utilization of vortex flow in the auxiliary combustion chamber 1 and to prevent fuel from adhering to the combustion chamber wall. and air mixing, thus promoting combustion. In addition, the outflow of gas from the auxiliary combustion chamber 2 to the main combustion chamber 1 is promoted, reducing the throttling loss at the auxiliary chamber nozzle, and promoting the mixing of fuel and air in the main combustion chamber 1, thus promoting combustion. can. The effect is particularly great when the inclination angle θ of the right circular cone according to claim 2 is within the range of 45°≦θ≦65°. Due to the above-mentioned functions and effects, and because the sub-combustion chamber 2 is provided near the center of the cylinder, the passage area of the sub-chamber nozzle can be expanded, the sub-chamber nozzle throttling loss and heat loss can be reduced, and the Over-dispersion of fuel can be prevented and combustion can be promoted, especially in the low load range. As described above, by implementing the present invention, fuel efficiency and smoke emissions can be improved, and noise and _NOx can be reduced.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a combustion chamber according to a first embodiment of the present invention.

FIG. 2 is a performance improvement diagram according to a second embodiment of the present invention.

FIG. 3 is a diagram corresponding to FIG. 1 of the conventional example.

[Explanation of symbols]

1 Main combustion chamber 2 Sub-combustion chamber 21 Upper part of auxiliary combustion chamber 22 Lower part of sub-combustion chamber 3 Antechamber nozzle 4 Cylinder head 5 Fuel injection valve 6 Piston 7 cylinder A-A Upper center line of auxiliary combustion chamber B-B Cylinder center line C-C Lower center line of sub-combustion chamber θ Inclination angle of the right circular cone ridgeline at the lower end of the upper part of the auxiliary combustion chamber

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Seiichi Sugiyama Mitsubishi Heavy Industries, 3000 Tana, Sagamihara City, Kanagawa Prefecture Inside Sagamihara Manufacturing Co., Ltd. (72) Creator Shiro Kodai Mitsubishi Heavy Industries, 3000 Tana, Sagamihara City, Kanagawa Prefecture Inside Sagamihara Manufacturing Co., Ltd. (72) Creator: Junhiro Fukuzawa Mitsubishi Heavy Industries, 3000 Tana, Sagamihara City, Kanagawa Prefecture Inside Sagamihara Manufacturing Co., Ltd.

Claims (2)

[Scope of utility model registration request] Claim 1: The sub-combustion chamber (2) is installed at or near the center of the cylinder, and in a sub-chamber engine having a plurality of sub-chamber nozzles (3), the sub-combustion chamber is a combination of hemispherical, cylindrical, and right circular conical shapes. The upper part of the auxiliary combustion chamber (21) is composed of the upper part of the auxiliary combustion chamber (21), and the lower part of the auxiliary combustion chamber (22) is made of a combination of a cylinder and a hemisphere. - It is inclined to the side opposite to the cylinder center line B-B with respect to A, is configured to generate a vortex (S) in the sub-combustion chamber during the compression stroke of the engine, and is disposed at the upper end of the sub-combustion chamber. A combustion chamber of a pre-chamber internal combustion engine, wherein the combustion injection valve (5) is installed so as to be able to inject fuel in a downstream direction of the vortex (S). [Claim 2] When the base angle of an isosceles triangle obtained by cutting the right circular cone provided at the lower part of the upper part (21) of the sub-combustion chamber along a plane including its axis is θ, 45°≦θ≦ 65°
The combustion chamber of a pre-chamber internal combustion engine according to claim 1, wherein the combustion chamber is configured to have the following configuration.