JPH0458012A - Auxiliary chamber type thermally insulated engine - Google Patents

Abstract

PURPOSE:To generate proper air mixture and suppress generation of NOx by providing, in a fuel injection nozzle, an auxiliary injection hole which injects at part of fuel to a glow plug arranged on the upstream side of swirl from a fuel injection stream line of the fuel injection nozzle. CONSTITUTION:A glow plug 5 which ignites a fuel injection nozzle 3 and air- mixture is arranged in an auxiliary chamber 2 an injection range of fuel injected from the fuel injection nozzle 3 is in a position it a specified area. The fuel injection stream line of the fuel injected from the fuel injection nozzle 3 is separated from the wall face 16 of an auxiliary chamber wall 8, and the fuel is injected in a swirl direction along the wall face 16. A part of fuel is injected to the glow plug 5 arranged on the upstream side of swirl from the fuel injection stream line of the fuel injection nozzle 3. Proper air-mixture is generated and burnt in this way, and generation of smoke, NOx and the like is suppressed so as to improve engine output.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a pre-chamber type adiabatic engine having a heat-insulating structure and having a pre-chamber provided with a fuel injection nozzle.

[Conventional technology]

Conventionally, the pre-chamber structure of an engine is, for example,
It is disclosed in Japanese Patent No. 07328. The sub-chamber structure of the engine disclosed in this publication includes a sub-chamber communicating with the main combustion chamber, the wall of the sub-chamber is made of a ceramic member, and a heat insulating space is formed around the outer periphery of the ceramic member. The insulation space is filled with a fibrous material with low thermal conductivity. The auxiliary chamber has a structure in which a fuel injection nozzle and a glow plug are provided.

In addition, the sub-combustion chamber of the sub-chamber type internal combustion engine is, for example,
It is disclosed in Japanese Patent No. 9-21024.

The auxiliary combustion chamber of the auxiliary chamber type internal combustion engine has a combustion chamber in the overflow chamber in the cylinder head, and the entire combustion chamber body of the overflow chamber combustion chamber is formed of a ceramic material, and the combustion chamber is made of the ceramic material. An air layer is formed in most of the fitting portion between the combustion chamber body and the cylinder head, and the cylinder side end of the fitting portion between the combustion chamber body and the cylinder head is gas-sealed with a sealing material. The insertion portion between the body and the insertion device is also gas-sealed with a sealing material.

[Problem to be solved by the invention]

However, the pre-chamber structure of the engine disclosed in the above-mentioned Utility Model Application No. 60-107328 and the above-mentioned Utility Model Application No. 59-2
Regarding the auxiliary combustion chamber of the auxiliary chamber type internal combustion engine disclosed in Publication No. 1024, the glow plug is located downstream of the swirl flow of the fuel injection nozzle, and the fuel from the fuel injection nozzle is directly injected into the glow plug. It is composed of Therefore, the air in the pre-chamber cannot be used effectively, and the mixture of the injected fuel and the swirl flow formed in the pre-chamber cannot necessarily form a good air-fuel mixture.
This has the problem of causing smoke, etc., and causing a decrease in engine output.

Furthermore, when the fuel spray from the fuel injection nozzle approaches the wall of the sub-chamber wall, the injected fuel with a large spray radius directly adheres to the wall of the sub-chamber wall, and becomes unburned gas. There is a problem with being discharged.

The purpose of this invention is to solve the above problems,
The auxiliary chamber provided in the cylinder end is constructed with ceramic material to obtain a high degree of heat insulation properties, and the fuel injection nozzle and glow plug are placed in the auxiliary chamber, so that the fuel injected from the fuel injection nozzle is optimized for swirl flow. The air is sprayed into the area to increase the air utilization rate, and is flowed in a swirl flow along the wall surface of the pre-chamber wall, producing a good air-fuel mixture and combusting it.
An object of the present invention is to provide a pre-chamber type adiabatic engine which suppresses the generation of smoke, N011, etc. and improves engine output.

[Means to solve the problem]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention provides a ceramic sub-chamber wall body that configures a sub-chamber that communicates with the main chamber with a heat-insulating structure, and a fuel injection line that is separated from the wall surface of the sub-chamber wall body and runs along the wall surface within the sub-chamber. A main injection hole provided in a fuel injection nozzle that injects fuel in a swirl direction, a glow plug disposed upstream of the swirl from a fuel injection streamline of the fuel injection nozzle, and the fuel that injects a part of the fuel into the glow plug. The present invention relates to a sub-chamber type adiabatic engine having a sub-nozzle provided in an injection nozzle.

In this pre-chamber type adiabatic engine, the distance between the fuel injection locus and the wall surface of the pre-chamber wall body is defined as the distance from the center point of the pre-chamber to the point where it perpendicularly intersects the fuel injection flow line. The ratio of the distance from the center point to the wall surface of the auxiliary chamber wall perpendicularly intersecting the fuel injection flow line is set to be approximately 30% or more.

[Effect]

The subchamber type adiabatic engine according to the present invention is constructed as described above, and operates as follows. That is, in this pre-chamber type adiabatic engine, the injection streamline of the fuel injected from the main injection hole of the fuel injection nozzle is separated from the wall surface of the pre-chamber wall body and is oriented in the swirl direction along the wall surface, and the fuel injection nozzle Since the configuration is such that a portion of the fuel from the auxiliary nozzle is injected into the glow plug placed upstream of the swirl from the fuel injection flow line of the auxiliary chamber, the injected fuel flows into the swirl along the wall surface of the auxiliary chamber wall and is injected into the air. A good air-fuel mixture is created by mixing with the fuel, which is then combusted. At this time, the combusted high-temperature gas has a light specific gravity, so it gathers in the center of the swirl, replacing the low-temperature air that was present in the center and continuing combustion. Moreover, when the injected fuel is placed along the wall surface, it is combusted from the outer periphery, so the air in the pre-chamber can be used more effectively, the generation of unburned gas such as smoke is reduced, and the engine output is improved. In addition, since the spray is on the outer periphery, the main combustion takes place in the low-temperature region, and the fuel flows into the gas atmosphere in the center of the pre-chamber and burns in a dry state, suppressing the production of NOx. .

[Embodiments] Hereinafter, embodiments of the pre-chamber type adiabatic engine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a cross-sectional view of an embodiment of the pre-chamber type adiabatic engine according to the present invention. This pre-chamber type adiabatic engine mainly consists of a cylinder block 11 having a hole 14, a cylinder liner 15 fitted into the hole 14, a cylinder head 10 fixed to the cylinder block 11 via a gasket 21, and a cylinder head 10 fixed to the cylinder block 11 via a gasket 21. A sub-chamber 2 formed in the sub-chamber 2, a fuel injection nozzle 3 and a glow plug 5 disposed in the sub-chamber 2, a piston 6 having a piston head 9 reciprocating within the cylinder liner 15, and the piston head 9.
It has a main chamber 1 which is formed into a main chamber 1 and communicates with a sub-chamber 2 through a communication hole 20. Further, an intake/exhaust port is formed in the cylinder 7/10, and an intake/exhaust valve is disposed in the intake/exhaust port (not shown).

Further, in this pre-chamber type adiabatic engine, the fuel injection nozzle 3 is provided with a main injection hole 4 and a sub-nozzle hole 13. That is, the fuel injection nozzle 3 has a nozzle body 18 and a needle valve 17 that moves up and down within the nozzle body 18 to open and close the main injection hole 4 and the sub injection hole 13. By opening the hole 4 and the sub-nozzle hole 13, the fuel in the fuel reservoir 19 is transferred to the sub-chamber 2.
It is used to inject into the air. Furthermore, the main nozzle 4 of the fuel injection nozzle 3 is configured to inject most of the fuel into the air in the auxiliary chamber 2, and the auxiliary nozzle 13 is configured to inject a small amount of fuel directly into the glow plug 5. There is.

In this fuel injection nozzle 3, the sub-nozzle hole 13 opens at the beginning of the upward movement of the needle valve 17, and then, as the lift amount of the needle valve 17 increases, the main nozzle hole 4 opens. Therefore, if this fuel injection nozzle 3 is used, when starting the engine, fuel is first injected from the sub-nozzle hole 13 to the glow plug 5, the fuel is ignited and burned, and then the lift amount of the needle valve 17 is reduced. As the fuel becomes larger, fuel is injected from the main nozzle hole 4 into the air in the auxiliary chamber 2, and combustion becomes active.

This pre-chamber type adiabatic engine particularly includes a fuel injection nozzle 3 and a glow plug 5 for igniting the air-fuel mixture in the pre-chamber 2,
This is because the injection area of the fuel injected from the fuel injection nozzle 3 is set at a predetermined location. In this configuration, the pre-chamber type adiabatic engine has the pre-chamber 2 constructed with a heat-insulating structure by the ceramic sub-chamber wall 8, and the fuel injected from the fuel injection nozzle 3 which injects fuel into the pre-chamber 2. A glow plug 5 whose streamline separates from the wall surface 16 of the sub-chamber wall body 8 and injects fuel in the swirl direction shown by the arrow along the wall surface 16, and is arranged on the swirl upstream side of the fuel injection streamline of the fuel injection nozzle 3. It is characterized by injecting a portion of the fuel into the fuel. In this case, as shown in FIG.
Fuel is injected into a swirl flow away from the wall surface 16 of the sub-chamber wall 8 and along the wall surface 16 from the main nozzle hole 4 of the fuel injection nozzle 3 in the swirl direction shown by the arrow, and the fuel is injected from the sub-nozzle hole 13 of the fuel injection nozzle 3 into the glow plug. 5 to inject part of the fuel. More specifically, as shown in FIG. 3, in this pre-chamber type adiabatic engine, the distance
The ratio of the distance S from the center point 0 of the auxiliary chamber 2 to the point where it perpendicularly intersects the fuel injection streamline F to the wall surface 16 of the auxiliary chamber wall 8 that intersects the fuel injection streamline F perpendicularly : The S/R was set to be approximately 30% or more. Here, the ratio of distance S to distance R: S/R expressed in % is called spray radius PR.

The auxiliary chamber 2 also includes a cast metal member 7 placed in a hole formed in the cylinder head 10 with an insulating air layer 12 in between, and a auxiliary chamber wall made of a ceramic material placed inside the cast metal member 7. It consists of 8 parts and has a highly insulated structure. In this pre-chamber type adiabatic engine, the pre-chamber wall body 8 constituting the pre-chamber 2 is made of aluminum titanate (ALTiO).
s) or silicon nitride (SisNa), silicon carbide (Si
C) A heat insulating structure made of ceramic materials such as composite materials.

Further, the cast metal member 7 is made of a metal material such as aluminum.

For this pre-chamber type adiabatic engine, the fuel injection nozzle 3
is for injecting fuel supplied from a fuel injection pump (not shown) into the auxiliary chamber 2. Further, for example, a fuel injection pump is provided with a pump operating pulley. This pump operating pulley is attached to the crankshaft and is drivingly connected to the crank pulley, which rotates together with the crankshaft, by a timing belt. Therefore, the fuel injection pump is driven by the timing heald as the engine is driven. Further, the fuel injection nozzle 3 may be an electric injection nozzle equipped with a needle valve that opens and closes electrically in response to commands from a controller (not shown). In that case, for example, in response to a command from the controller, the fuel injection nozzle 3 can be controlled so that the needle valve opens during the first half of the compression stroke to inject fuel into the subchamber 2.

Since the subchamber type adiabatic engine according to the present invention is constructed as described above, it operates as follows.

In this pre-chamber type adiabatic engine, the fuel injected from the main nozzle hole 4 of the fuel injection nozzle 3 is injected into a swirl flow area away from the wall surface 16 of the pre-chamber wall body 8, and is mixed well while flowing in the swirl flow. The generation of particles is reduced by generating and burning air, and the fuel is injected not into the high-temperature area in the center but into the low-temperature area near the wall surface 16, and the main combustion occurs in the fuel lynch in the 61-area, which reduces NOx. Occurrence is suppressed. That is, the injected fuel from the fuel injection nozzle 3 is swirled along the wall surface 16 of the sub-chamber wall 8 and mixed with air to generate an air-fuel mixture, which is then combusted.

At this time, the combusted high-temperature gas has a light specific gravity, so it gathers in the center of the swirl, replacing the low-temperature air that was present in the center and continuing combustion. Moreover, the injected fuel is
Since combustion occurs from the outer periphery, the air in the subchamber 2 can be used more effectively, reducing the generation of unburned gas such as smoke, and improving output. In addition, since the spray from the fuel injection nozzle 3 is on the outer periphery, the fuel flows into the gas atmosphere in the center of the auxiliary chamber 2 and burns in a dry state, suppressing the generation of NOx. .

Furthermore, in this pre-chamber type adiabatic engine, the pre-chamber wall 8 of the pre-chamber 2 is made of ceramic material and the pre-chamber 2 has a heat-insulating structure, so the wall surface 16 of the pre-chamber wall 8 becomes hot. Since it is retained, the increase in hydrocarbon HC is suppressed.

Next, in order to compare this pre-chamber type adiabatic engine with the case where the fuel injection nozzle is placed in the standard setting position, we will compare the case where the installation position of the fuel injection nozzle 3, that is, the injection direction, is changed and the fuel is injected. The test results, i.e., the order amount (%) of smoke corresponding to various injection radii, that is, spray radius SR (%) of the fuel injection nozzle 3, the net average effective pressure (kgf/cm'), and the generation amount of No. pp
m) are shown in FIGS. 4, 5 and 6. Figure 4 is a diagram showing the relationship between the spray radius SR of the fuel injection nozzle and the amount of smoke generated, Figure 5 is a diagram showing the relationship between the spray radial of the fuel injection nozzle and the net average effective pressure, and Figure 6 is a diagram showing the relationship between the spray radius SR of the fuel injection nozzle and the net average effective pressure. are the spray radius SR and NO of the fuel injection nozzle
FIG. 3 is a diagram showing the relationship with the amount of X generated.

In FIG. 4, the amount of smoke generation (%) is plotted on the vertical axis, and the spray radius SR (%) is plotted on the horizontal axis. Smoke generation amount (%) is standard ST
It can be seen that the case where the spray radius is 5R 34, 58% is smaller than the case where the spray radius 5R is 22, 64% in D. That is, it can be seen that in order to reduce the amount of smoke generated, it is preferable to set the spray radius SR to about 30% or more.

In Figure 5, the vertical axis shows the net average effective pressure (kgf/cm
2) is plotted, and the horizontal axis is the spray radius SR (
%) is proa). It can be seen that the net average effective pressure has almost no effect on the proportion of spray radius SR. Here, the net average effective pressure P■ is the value obtained by dividing the amount of work in each cycle corresponding to the shaft output by the total stroke volume kgf/c1
It is 112. That is, P□ −kP,! /nV,.

However, P: Shaft output (kW) - n: Rotation speed rpmV, t
: total stroke volume (J), k: constant In FIG. 6, the vertical axis plots the NOx order amount (ppm), and the horizontal axis plots the spray radius SR (%).

It can be seen that the amount of NoX generated (<ppm) is smaller in the case of spray radius 5R34, 58% compared to the case of standard STD spray radius 5R22: 64%. That is, it can be seen that in order to reduce the amount of NOx generated, it is preferable to set the spray radius SR to about 30% or more.

Furthermore, the pre-chamber type adiabatic engine of the present invention has the pre-chamber 2 having an insulating structure to recover thermal energy and to avoid combustion in the NOx generation zone, so that the equivalence ratio of the fuel to be mainly combusted is kept in a lynch state. The method is to burn it. Therefore, combustion in the pre-chamber 2 ignites the air-fuel mixture in a rich state and burns at a high temperature, so combustion in the No. 8 generation zone can be avoided, and flames are not blown out from the pre-chamber 2 to the main chamber 1. As a result, the air-fuel mixture suddenly becomes lean, and the combustion temperature decreases, making it possible to avoid combustion in the No. 8 generation zone.

Therefore, the generation of NOx can be reduced throughout the combustion time of the air-fuel mixture.

〔Effect of the invention〕

Since the pre-chamber type adiabatic engine according to the present invention is configured as described above, it has the following effects. That is, in this pre-chamber type adiabatic engine, the pre-chamber wall body is made of ceramic and has a heat-insulating structure, and the fuel injection flow line is separated from the wall surface of the pre-chamber wall body and flows along the wall surface to create a swirl inside the pre-chamber. A main injection hole provided in a fuel injection nozzle that injects fuel in a direction, a glow plug disposed upstream of a swirl from a fuel injection streamline of the fuel injection nozzle, and the fuel injection that injects a part of the fuel to the glow plug. Since the nozzle has a sub-nozzle hole, the fuel injected from the sub-nozzle hole is first injected directly into the glow plug to ignite and burn, and then the fuel is injected from the main nozzle hole, and the injected fuel Hydrocarbon is injected into the swirl region without adhering to the wall surface of the sub-chamber wall body, is carried by the swirl flow, produces a good air-fuel mixture, and is combusted in the outer peripheral region of the sub-chamber. In addition to suppressing the generation of particles, the fuel is injected into the low temperature area near the wall surface instead of the high temperature area in the center, and the main combustion is performed by fuel lynching in the low temperature outer peripheral area, so the generation of NOx is suppressed. .

That is, the injected fuel from the fuel injection nozzle is swirled along the wall surface of the auxiliary chamber wall, mixes with air, generates an air-fuel mixture, and is combusted. At this time, the combusted high-temperature gas has a light specific gravity, so it gathers in the center of the swirl, replacing the low-temperature air that was present in the center and continuing combustion. Moreover, when the injected fuel is placed along the wall surface, it burns from the outer periphery, so the air in the pre-chamber can be used more effectively, reducing the generation of unburned gas such as smoke,
Improve output. In addition, since the spray from the fuel injection nozzle is on the outer periphery, the fuel flows into the gas atmosphere in the center of the auxiliary chamber, burns in a dry state, and produces NO.
The generation of x can be suppressed. Moreover, since the sub-chamber wall constituting the sub-chamber has a heat insulating structure made of ceramic material, the wall surface of the sub-chamber wall is maintained at a high temperature, thereby suppressing an increase in hydrocarbon HC. be done.

In this pre-chamber type adiabatic engine, the distance between the fuel injection locus and the wall surface of the pre-chamber wall body is defined as the distance from the center point of the pre-chamber to the point where it perpendicularly intersects the fuel injection flow line. Since the ratio of the distance from the center point to the wall surface of the auxiliary chamber wall perpendicularly intersecting the fuel injection flow line is set to be approximately 30% or more, the distance from the main injection hole of the fuel injection nozzle is Fuel injection is in the optimum range of swirl flow, and smoke generation and N2 are reduced without reducing engine output.
Generation of OX can be suppressed.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing one embodiment of the pre-chamber type adiabatic engine according to the present invention, Fig. 2 is an explanatory diagram showing an example of the fuel injection nozzle of Fig. 1, and Fig. 3 is an explanatory diagram showing an example of the fuel injection nozzle of the fuel injection nozzle. Fig. 4 is a diagram showing the relationship between the spray radial of the fuel injection nozzle and the amount of smoke generated, and Fig. 5 is a diagram showing the relationship between the spray radial of the fuel injection nozzle and the net average effective pressure. The diagrams shown in FIG. 6 and FIG. 6 are diagrams showing the relationship between the spray radial of the fuel injection nozzle and the amount of NoX generated. 1-11---Main chamber, 2----1 Subchamber, 3-----Fuel injection nozzle, 4.-----11 Main injection hole, 5-----
Glow plug, 6...Piston, 7...-Cast metal, 8...-Sub chamber wall, 9 Piston head, cylinder head, sub nozzle hole, wall surface.

Claims (2)

[Claims] (1) A ceramic sub-chamber wall body that configures a sub-chamber communicating with the main chamber with a heat-insulating structure, and the fuel injection flow line is separated from the wall surface of the sub-chamber wall body and is directed along the wall surface in the swirl direction within the sub-chamber. A main injection hole provided in a fuel injection nozzle that injects fuel, a glow plug disposed upstream of the swirl from a fuel injection flow line of the fuel injection nozzle, and the fuel injection nozzle that injects a part of the fuel to the glow plug. A pre-chamber type adiabatic engine with a sub-nozzle hole provided. (2) The distance from which the fuel injection locus leaves the wall surface of the sub-chamber wall body is defined as the distance from the center point of the sub-chamber to perpendicularly intersecting the fuel injection streamline, and the distance from the center point of the sub-chamber to the fuel injection streamline. 2. The pre-chamber type adiabatic engine according to claim 1, wherein the ratio of the distance to the wall of the pre-chamber wall perpendicularly intersecting with the pre-chamber wall is approximately 30% or more.