JPH08284665A - Combustion control method for engine and its device - Google Patents

Abstract

PURPOSE: To efficiently reduce HC and NOx by igniting air-fuel mixture inside a sub-chamber by means of an ignition plug, injecting the generated frame to an outer peripheral part of a combustion chamber, intorucing combustible air-fuel mixture inside the combustion chamber into a sub-chamber, self-igniting it inside the sub-chamber, and injecting it as frame. CONSTITUTION: A sub-chamber 10 having an ignition gap 12a is formed on substantially a center of a combustion chamber 1. The sub-chamber 10 is communicated with the combustion chamber 1 through infection ports 21, 22. The injection port 21 is directed to an outer peripheral part of the combustion chamber from two intake port side. The injection port 22 is directed to the outer peripheral part from two intake port side. When air-fuel mixture in the combustion chamber 1 is introduced into the sub-chamber 10, ignition is performed by the ignition gap 12a. Frame generated in the sub-chamber 10 is injected to the outer peripheral part of the combustion chamber as initial injection flow frame from the injection ports 21, 22. Combustible air-fuel mixture is introduced into the sub-chamber 10 from the combustion chamber 1, and self- ignited inside the sub-chamber 10. The generated frame is injected to the combustion chamber 1 as later frame.

Description

Detailed Description of the Invention

[0001]

The present invention relates to relates to a combustion control method and apparatus for an engine to be able to significantly reduce the NO _X and HC.

[0002]

2. Description of the Related Art Some engines have a combustion chamber (main combustion chamber).
In addition to the above, there is proposed one having a sub chamber (sub combustion chamber) communicated with the combustion chamber through a nozzle hole (communication port). One in which an ignition gap is located in this sub-chamber is disclosed in Japanese Patent Laid-Open No.
Japanese Patent Laid-Open No. 1-2810 and Japanese Patent Laid-Open No. 51-55810 disclose both of them for improving the ignitability when performing lean combustion. Further, as a device in which the ignition gap is not located in the sub chamber, it is disclosed in JP-A-62-233416.
Japanese Patent Laid-Open Publication No. 2003-242242 discloses that in a diesel engine, self-ignition is performed in the sub chamber in the latter stage of combustion to end combustion early.

[0003]

By the way, recently,
Exhaust gas purification is strongly desired, especially HC and NO
_X The drastic reduction of is desired. Such HC and
NO_X After using the exhaust gas purification catalyst,
Not by processing, but by improving the combustion of the engine itself
It is hoped that this can be achieved.

Therefore, it is an object of the present invention to use HC and N
The O _X to provide a combustion control method and apparatus of an engine to be significantly reduced.

In order to achieve the above object, the method of the present invention has the following configuration. That is, the sub chamber having the injection holes directed to the outer peripheral edge of the combustion chamber and having the ignition gap inside is disposed, and the air-fuel mixture in the sub chamber is ignited by the ignition gap, and the flame generated in the sub chamber. Is injected from the injection hole toward the outer peripheral edge of the combustion chamber, a second step of introducing an unburned air-fuel mixture in the combustion chamber into the sub chamber, and an unburned air mixture introduced into the sub chamber. A third step of self-igniting in the sub chamber to eject a flame from the injection hole.
Preferred embodiments of the present invention based on the above configuration are as described in claims 2 to 9 in the claims.

In order to achieve the above object, the device of the present invention has the following configuration. That is, a sub-chamber having an injection hole directed to the outer peripheral edge of the combustion chamber and having an ignition gap inside is disposed, and the setting of the sub-chamber and the injection hole is performed by setting the air-fuel mixture in the sub-chamber by the ignition gap. By igniting, the flame generated in the sub chamber is ejected from the injection hole toward the outer peripheral edge of the combustion chamber, and after the initial combustion, the unburned air-fuel mixture in the combustion chamber is introduced into the sub chamber. The secondary combustion is performed by self-ignition in the sub chamber and the flame is ejected again from the injection hole. Preferred embodiments of the present invention based on the above configuration are as set forth in claim 11 and the following claims.

[0007]

According to the invention described in claim 1 or claim 10, the air-fuel mixture ignited by the ignition gap is ejected from the injection hole toward the outer peripheral edge of the combustion chamber. At this time, the initial combustion ratio becomes sufficiently small (retardation at the time of maximum heat generation), and NO _X, which easily occurs due to the large initial combustion ratio, is greatly reduced. Also,
HC is likely to be generated by the flame in the initial combustion toward the outer peripheral edge of the combustion chamber, and the combustion in the outer peripheral edge of the combustion chamber is satisfactorily performed early and HC is significantly reduced.

Further, since the temperature and pressure inside the combustion chamber become high due to the initial combustion, a large amount of activated chemical species having a high energy state as well as the unburned mixture in the combustion chamber is introduced into the sub chamber through the injection holes. Not only is auto-ignition in the sub-chamber to further reduce HC, but also the reduction reaction utilizing the active chemical species is promoted to further reduce NO _X.

In addition to this, since the initial combustion ratio is small, knocking is suppressed, which is advantageous in terms of securing output. Of course, in the present invention, the ignitability is also improved by the ignition utilizing the ignition gap in the sub chamber, and the ignitability when the air-fuel ratio is sufficiently leaner than the stoichiometric air-fuel ratio is also improved as compared with the normal engine. It is also possible to improve fuel efficiency.

With the structure as set forth in claim 2, since the mixture gas is supplied from the combustion chamber to the sub chamber through the injection holes, the gas for self-ignition in the sub chamber is also injected from the combustion chamber. Since it is performed through the holes, combustion control as a whole is extremely simple.

By adopting the structure as described in claim 3, it is convenient for reaching the flame of the initial combustion from the sub chamber to the outer peripheral edge of the combustion chamber, and the arrangement of the spark plug is the same as in a normal engine. This is preferable because it can be made substantially the center of the combustion chamber.

The structure as described in claim 4 is preferable for further reducing the combustion ratio at the initial stage of combustion.

According to the fifth aspect of the present invention, it is preferable to reduce the HC by directing the flame of the initial combustion to the vicinity of the intake valve where the rich air-fuel mixture is unevenly distributed and HC is likely to be generated. Become.

With the structure as described in claim 6, it is possible to obtain the effect corresponding to claim 5 with respect to a recent engine, particularly, an intake two-valve type engine which is generally used as an automobile engine.

With the structure as described in claim 7, the swirl of the intake air is utilized to rapidly grow the flame in the circumferential direction of the outer peripheral edge of the combustion chamber to reduce the HC, and also the flame. which is preferable in reducing the NO _X and to reduce the area from early to the initial combustion ratio more sufficiently small.

The structure as described in claim 8 is preferable for improving the ignitability and for making the air-fuel ratio lean due to the ignitability improvement.

The construction as described in claim 9 is preferable in order to sufficiently obtain the fuel consumption improvement which is strongly required at the time of low load.

With the structure described in claim 11, fuel can be supplied in the same manner as in a normal engine.

With the structure described in claim 12, it is possible to obtain the same effect as the effect corresponding to claim 4.

With the structure as described in claim 13, it is possible to obtain the same effect as the effect corresponding to claim 5.

By adopting the structure as described in claims 14 to 19, it is possible to provide a specific structure for setting the sub chamber and the injection hole.

By configuring as described in claim 20, the sub-chamber is formed substantially as an integral spark plug,
This is preferable because the maintenance and inspection can be carried out in the same manner as the maintenance and inspection of the spark plug, and it is also easy to apply to the existing engine.

With the configuration as described in claim 21, maintenance and inspection of the spark plug can be performed in the same manner as a normal engine. In addition, the sub chamber constituent members,
The material of the sub-chamber has a high degree of freedom, such as that the material can be optimally set for combustion according to the invention.

With the structure described in claim 22, the sub chamber can be manufactured at the same time as the cylinder head is manufactured.

With the structure as set forth in claim 23, it is preferable for optimizing the shape of the combustion chamber without being disturbed by the sub chamber as much as possible and for preventing overheating of the sub chamber. Become.

With the structure as set forth in claim 24, it is preferable for optimizing the material forming the auxiliary chamber and simplifying the case of forming the auxiliary chamber in the cylinder head.

According to the twenty-fifth aspect of the present invention, the tumble is utilized before self-ignition,
This is preferable for sufficiently introducing the unburned air-fuel mixture in the combustion chamber and the activated chemical species in a high energy state into the sub chamber.

With the structure as set forth in claim 26, it is preferable for suppressing the growth of the flame from the outer peripheral edge of the combustion chamber toward the center of the combustion chamber and reducing the initial combustion ratio.

With the structure as described in claim 27, H at the outer peripheral edge of the combustion chamber which becomes a problem at low load
This is preferable for sufficiently reducing C and for suppressing the early combustion ratio by suppressing early combustion of the rich air-fuel mixture portion at the time of high load.

With the structure as described in claim 28, the outer peripheral edge of the combustion chamber is sufficiently burned by the initial flame ejected from the injection hole, and the heat load on the piston is prevented from becoming excessive. It is preferable for doing so.

According to the structure described in claim 29, the collision angle of the initial flame ejected from the injection hole to the cylinder wall surface is relaxed and the flame is grown in the circumferential direction at the outer peripheral edge of the combustion chamber. It is preferable for reducing HC and for sufficiently introducing unburned air-fuel mixture or high-energy activated chemical species into the sub chamber from the injection hole for later self-ignition.

With the structure as set forth in claim 30, it becomes preferable for increasing the turbulence of the gas in the combustion chamber due to the pre-injection of the compressed air-fuel mixture from the injection hole (the unburned air-fuel mixture). And increase the disturbance effect of active chemical species).

With the structure described in claim 31, the effect corresponding to claim 30 can be obtained by a simple method of setting the distance between the ignition gap and the injection hole.

With the structure as described in claim 32, it is possible to obtain the effect corresponding to claim 8 and to improve the fuel consumption.

With the structure as described in claim 33, it is possible to obtain the effect corresponding to claim 32 while sufficiently improving the fuel consumption.

With the structure as described in claim 34, the combustion in the outer peripheral edge of the combustion chamber is performed well, and the HC
It is more preferable in terms of reduction.

With the structure as set forth in claim 35, combustion in the outer peripheral edge portion of the sister combustion chamber, which is particularly problematic during cold, is satisfactorily performed, which is more preferable in terms of HC reduction.

With the structure as set forth in claim 36, ignition in a region of the outer peripheral edge of the combustion chamber where the ignitability is poor can be reliably performed by using a separately provided spark plug to sufficiently reduce HC. In addition, it is preferable for promoting turbulence in the combustion chamber.

With the structure as described in claim 37, in order to more surely perform self-ignition in the sub chamber,
In addition, it is preferable for promoting the late combustion due to self-ignition.

According to the structure described in claim 38, the flame arrival at the initial combustion on the intake valve side where the flame propagation is good and the exhaust valve side where the flame propagation is not good is made almost the same, This is preferable in that the effect corresponding to claim 10 is sufficiently obtained. In particular, it is suitable for a large displacement engine in which the cylinder diameter becomes large and a difference in flame propagation speed tends to be a problem.

With the construction as set forth in claim 39, the unburned air-fuel mixture and the activated chemical species in the combustion chamber can be sufficiently introduced into the sub-chamber through the nozzle holes for self-ignition in the sub-chamber. In addition, it is preferable for sufficiently improving fuel efficiency and sufficiently performing late combustion by self-ignition.

With the construction as set forth in claim 40 or claim 41, for the purpose of self-ignition in the sub-chamber, the unburned air-fuel mixture and the activated chemical species in the combustion chamber are sufficiently passed through the nozzle holes. It is preferable for the introduction into the.

With the construction as described in claim 42, the unburnt air-fuel mixture and the active chemical species in the combustion chamber can be sufficiently passed through the nozzle hole for self-ignition in the sub chamber by utilizing the communication port. It is preferable for introducing it into the sub chamber.

With the construction as set forth in claim 43, the jetting of the flame of the latter stage combustion due to self-ignition in the sub-chamber also utilizing the communication port further promotes the oxidation and reduction reactions in the combustion chamber. Te, HC, becomes more preferable over of the NO _X reduction.

By adopting the structure as described in claim 44, a more specific structure of the communication port for obtaining the effect corresponding to claim 43 is provided.

The structure as set forth in claim 45 is preferable for promoting ignition and self-ignition due to the ignition gap in the sub chamber.

With the structure as set forth in claim 46, even when the self-ignition in the sub-chamber becomes impossible, the desired combustion state is ensured by supplementing the ignition gap with another ignition. Can be obtained.

With the structure as described in claim 47, the same effect as the effect corresponding to claim 43 can be obtained.

By virtue of the structure as set forth in claim 48, prevention of overheating of the sub-chamber during warming (improvement of knocking performance) and prevention of over-cooling of sub-chamber during cold (ignition resistance) (Securing) is satisfied, and it is preferable in order to sufficiently exert the effect corresponding to claim 10.

With the structure as set forth in claim 49, the number of sub-chambers, that is, the number of ignition gaps is set to the minimum necessary one, and the outer peripheral edge portion of the combustion chamber is swiftly extended over almost the entire length in the circumferential direction of the combustion chamber. A preferable one is obtained for burning.

[0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings.

(1) Basic explanation of the present invention (see FIG. 1)
(Fig. 7)

First, the basic principle of the present invention will be described with reference to FIGS. First, in FIG. 1 and FIG.
Reference numeral 1 denotes a combustion chamber of a reciprocating ignition engine, which is formed in the cylinder head SH as is known. Combustion chamber 1
Is a pentorf type having two inclined surfaces 1a and 1b, and the ridgeline where the inclined surfaces 1a and 1b intersect is designated by α.
Indicated by. The ridge line α extends parallel to the crank shaft (not shown).

On one inclined surface 1a, two intake ports 2 and 3 are opened at intervals in the ridge line α direction. Further, on the other inclined surface 1b, two exhaust ports 4 and 5 are opened at intervals in the ridge line α direction. Each intake port
The ports 2 and 3 are opened to one side surface of the cylinder head 1 (right side in FIG. 1), and the exhaust ports 4 and 5 are opened to the other side surface of the cylinder head SH (left side in FIG. 1). S
Intake is introduced from one side surface of H and exhausted from the other side surface of the cylinder head SH, a so-called cross flow.
It is a type. Of course, although not shown, the intake ports 2 and 3 and the exhaust ports 4 and 5 are synchronized with the rotation of the crankshaft at a well-known timing by the umbrella valve type intake valve or exhaust valve. It is opened and closed.

One sub-chamber 10 is arranged at the approximate center (center or its vicinity) of the combustion chamber 1 through which the ridge line α passes. This sub chamber 10 is sufficiently smaller than the volume (minimum volume) of the combustion chamber 1. The sub chamber 10 is configured using a bottomed cylindrical sub chamber constituent member 11 fixed to the cylinder head SH by screwing or the like. That is, the spark plug 12 is screwed into the upper end of the sub chamber constituent member 11 having an opening at the upper side, and the upper opening of the sub chamber constituent member 11 is covered by the spark plug 12. That is, sub-chamber 1
0 is defined by the auxiliary chamber constituent member 11 and the ignition plug 12, and the ignition gap 12 a of the ignition plug 12 is positioned in the auxiliary chamber 10. The spark plug 12 is the same as that used in a normal engine (M1
4), the maximum diameter of the sub chamber 10 is the screw portion 1 of the spark plug 12.
It is the same as the outer shape of 2b.

The bottom of the sub-chamber constituting member 11 slightly protrudes into the combustion chamber 1, and the protruding portion into the combustion chamber 1 has
Two first and second injection holes 21 and 22 are formed to connect the combustion chamber 1 and the sub chamber 10 with each other. The injection holes 21 and 22 have the same length and diameter (opening area),
The volume of the sub chamber 10 is set to have a predetermined dimension as described later.

Each of the injection holes 21 and 22 is directed toward the outer peripheral edge of the combustion chamber. That is, the directivity line between the injection holes 21 and 22 extends in a direction (cylinder radial direction) that passes through substantially the center of the combustion chamber 1 and is substantially orthogonal to the ridgeline α when viewed from the cylinder axis direction. The directions are opposite to each other (the injection holes 21 and 22 are 1 in the circumferential direction of the combustion chamber).
Formed at 80 degree intervals). More specifically, the first injection hole 21
Is in the direction of the two intake ports 2 and 3, that is, toward the intake valve,
It is oriented so as to pass through the intermediate position of the intake ports 2 and 3. The second injection hole 22 is oriented in the direction of the exhaust ports 4 and 5, that is, in the direction of the exhaust valve so as to pass through the intermediate position of the exhaust ports 4 and 5. In addition, each injection hole 21, 2
As shown in FIG. 2, 2 is oriented near the outer peripheral edge of the top surface of the piston 6 near the top dead center, that is, the piston clevis, in a plane parallel to the cylinder axis. The fuel supply to the combustion chamber 1 is performed by the fuel injection valve 7 as in a normal engine.
From the intake ports 2 and 3.

In the above-described structure, in the intake stroke, intake air is supplied from the intake ports 2 and 3 and fuel is injected from the fuel injection valve 7 into the combustion chamber 1 to mix the mixture in the combustion chamber 1. Is formed. In the compression stroke, (a part of) the air-fuel mixture in the combustion chamber 1 is introduced into the sub chamber 10 through the injection holes 21 and 22.

When the predetermined ignition timing is reached, the ignition gap 12a is ignited. As a result, the flame ignited in the sub chamber 10 and ignited in the sub chamber 10 is
A thin flame from 22 is jetted vigorously into the combustion chamber 1 (initial combustion due to generation of initial jet flow). These injection holes 21, 22
The flame ejected from the flame reaches the outer peripheral edge of the combustion chamber and grows in the circumferential direction of the outer peripheral edge of the combustion chamber, but the flame that reaches the outer peripheral edge of the combustion chamber is growing in the circumferential direction of the combustion chamber. Are shown in FIGS.

The flame toward the outer peripheral edge of the combustion chamber grows in the circumferential direction of the combustion chamber, and the state in which this growth progresses is shown in FIGS. 3 and 4, but the flame at the outer peripheral edge of the combustion chamber does not reach the center of the combustion chamber. Does not grow enough. That is, since the flames from the injection holes 21 and 22 are jet flames, the flames reach the outer peripheral edge of the combustion chamber and the flames grow in the circumferential direction of the combustion chamber thereafter quickly, but the flames grow toward the center of the combustion chamber 1. It will be slow. Then, before the flame reaches the center of the combustion chamber, the flame grows over almost the entire length of the outer peripheral edge of the combustion chamber, and a ring-shaped flame is generated (the reaction zone area of the flame surface gradually decreases). .

In the state shown in FIGS. 3 and 4 where the flame is growing in the circumferential direction of the combustion chamber at the outer peripheral edge of the combustion chamber, the sub chamber 10
Since the combustion inside has ended, the pressure in the combustion chamber 1
It is sufficiently higher than the pressure in the sub chamber 10. This allows
The unburned air-fuel mixture in the combustion chamber 1 and the activated chemical species (radicals) in a high energy state are introduced into the sub chamber 10 through the injection holes 21 and 22. Then, in the sub-chamber 10, it is activated by mixing the radicals and the unburned air-fuel mixture,
Eventually, the sub-chamber 10 is self-ignited (the period until this self-ignition is medium-term combustion).

The flame generated by self-ignition in the sub chamber 10 is, as shown in FIGS. 5 and 6, the injection holes 21 and 22.
Will be ejected to the combustion chamber 1 through (the latter combustion in which the latter jet is generated).

The state of heat generation due to the above-mentioned combustion is shown in FIG. In FIG. 7, what is indicated by a broken line is
The figure shows a heat generation mode in a normal engine in which only the ignition gap is arranged in the center of the combustion chamber. As is apparent from FIG. 7, in the heat generation mode of the present invention, the time of the heat generation peak (the center of gravity of heat generation) showing the maximum heat generation is retarded, that is, the initial combustion ratio is smaller than that of a normal engine. To be taken.
Further, the heat generation start time is later than that of the normal engine, and the combustion end time is earlier than that of the normal engine, so that the combustion period is shortened as a whole.

Next, the mechanism of HC reduction and NO _X reduction will be explained. First, HC reduction will be explained.

First, the outer peripheral edge portion of the combustion chamber is early covered with the flame by the initial jet flow, that is, the initial flame flowing from the injection holes 21 and 22 toward the outer peripheral edge portion of the combustion chamber. This prevents the unburnt air-fuel mixture from being pushed into the piston clevis, promptly burns the unburnt air-fuel mixture that has entered the piston clevis, raises the gas temperature in the cylinder outer periphery due to the Hopkinson effect, and oxidizes unburned HC during the expansion stroke. H by promotion
C is reduced.

Secondly, there is a reduction in HC due to the disturbing effect of the initial jet flame ejected from the injection holes 21 and 22. That is, by giving disturbance to the combustion field, the quench (extinguishing) distance is shortened, and so-called wall surface quench is reduced, thereby reducing HC. Further, there is a reduction in HC due to an increased probability of collision between unburned HC existing in the propagating flame and residual oxygen due to the disturbance.

Third, there is a reduction in HC by improving the burning rate of the liquid fuel due to the initial jet flame. That is, the liquid fuel (which is remarkable especially when the fuel amount is increased during cold) adheres to the vicinity of the intake valve and is a major cause of HC generation, but the liquid fuel is generated by the initial jet flame from the first injection hole 21. Sufficiently burned to reduce HC.

Fourthly, there is HC reduction utilizing the disturbance effect by the late jet flame that occurs after self-ignition.

Fifth, radicals and combustion caused by the late jet flame
H by promoting chemical reaction with unburned HC existing in the entire baking chamber
There is a C reduction. That is, for example, “HC + OH radical
= H ₂ O + CO₂ Reaction is promoted and HC is reduced.
It

The NO _X reducing mechanism is as follows.

First, as is clear from FIG. 7, there is a reduction in NO _X by the retardation of the center of gravity of the heat generation pattern.
In particular, since the combustion at the initial stage of combustion where the NO _x generation rate is large is suppressed (combustion temperature is suppressed), the NO _x is greatly reduced. At the beginning of combustion, since it is a jet flame, the jet flame that passes through the burned part after the initial jet flame once passes, so the initial combustion rate, that is, the initial heat generation temperature is suppressed to a low value, and NO _x reduction Becomes Also, since the initial jet flame reaches the wall surface of the cold peripheral edge of the combustion chamber,
In particular, NO _X reduction at the early stage of combustion with a high NO _X emission rate can be obtained.

Secondly, since the flame surface grows rapidly in the circumferential direction of the combustion chamber and slowly grows toward the center of the combustion chamber, when flame coalescence in the circumferential direction of the combustion chamber can be obtained, the effect of gradually reducing the flame area is obtained. It is possible to expect a decrease in the maximum calorific value.
O _X reduction to become.

Third, the late jet flame reduces NO _X by improving the probability of collision between NO _X generated in the entire combustion chamber and a reducing agent such as radicals. Further, NO by chemical reaction promoting whether radicals and NO _X by late Jet flame
_X reduction. That is, for example, the reduction reaction of “NO + CH radical = N ₂ + H ₂ O + CO ₂ ” is promoted, and N
O _X reduction to become.

In addition to the above, according to the present invention, by the early combustion in the outer peripheral edge of the combustion chamber and the reduction of the combustion ratio in the initial stage of combustion,
The knocking resistance will be improved. Further, ignition is possible even if the air-fuel ratio is sufficiently lean (for example, the air-fuel ratio is 20 or more), and the production of the latter-stage jet flame is more likely to occur sufficiently when it is lean than when it is rich. The fuel economy can be improved by making the engine lean.

Here, the specific setting of the injection holes 21 and 22 and the sub chamber 10 for obtaining the above-mentioned combustion will be described. Now, assuming that the surface areas of the injection holes 21 and 22 are Acm ² and the volume of the sub chamber 10 is Vcm ³ , A / V is (1 /
cm) is set to fall within the range of 3.0 × 10 ^{−3 to} 1.5 × 10 ⁻² . In addition, the number of injection holes 21 and 22 is n
When the number is A / n / V (1 / cm) is 7.5 ×
It is set to be in the range of 10 ^{−3 to} 3.0 × 10 ⁻² . The surface area A of the injection holes 21 and 22 is the inner surface area obtained by multiplying the circumferential length and the axial length.

When the cylinder bore diameter is less than 83 mm,
The volume V of the sub chamber 10 is set to be less than 1.0 cm ³ , or the length L of the injection holes 21 and 22 is set to be less than 2.8 mm, which are set to satisfy at least one condition. .

When the cylinder bore diameter is 83 mm or more,
The volume V of the sub chamber 10 is set to 1.0 cm ³ or more, or the length L of the injection holes 21 and 22 is set to 2.8 mm or more so as to satisfy at least one condition. .

(2) Preferred embodiment of the present invention (FIGS. 8 to 1)
7)

Description of FIG. 8 In the embodiment of FIG. 8, the auxiliary chamber constituent member 11 and the spark plug 12 are integrated. That is, the sub chamber constituent member 11 is fixed to the ignition plug 12 by screwing or the like so as to surround the ignition gap 12a (may be fixed by welding or the like). In addition, the sub chamber constituent member 1
1 has an external thread 11a formed on the outer periphery thereof, and the external thread 1
1a is made to function as a screw portion for mounting an engine in a normal spark plug. According to the present embodiment, the above-described combustion mode can be obtained without making any special change to the existing engine. Further, the maintenance and inspection of the sub chamber 10 can be easily carried out by removing a normal spark plug from the engine.

Description of FIG. 9 The embodiment of FIG.
Is integrally formed with the cylinder head SH.
That is, a sub-chamber bottom wall portion 31 corresponding to the sub-chamber tip (bottom wall) portion is formed near the center of the combustion chamber 1, and the sub-chamber bottom wall portion 3 is formed.
1, the injection holes 21 and 22 are formed later by drilling from the direction indicated by the alternate long and short dash line in the figure.
Depending on the formation angle of the injection holes 21 and 22, the notch 32 may be formed in a part of the outer peripheral edge of the combustion chamber 1 so as not to interfere with the drilling process.

Description of FIG. 10 and FIG. 11
In this embodiment, the tip end (bottom wall) component member 33 of the sub chamber as shown in FIG. 11 is cast during the casting of the cylinder head SH, and a part thereof is cooled water passage 34 of the cylinder head SH.
It is made to project inside. Then, later, the upper portion of the tip forming member 33 is shaved together with the cylinder head SH so as to obtain the sub chamber 10 having a predetermined volume, and the injection holes 21 and 22 are further cut in the tip forming member 33 by cutting. Has been formed. The sub-chamber 10 has an opening above it, and the spark plug 12 is screwed therein as in the case of FIG. The tip constituent member 33 is preferably made of a material having excellent heat resistance, for example, a super Ni alloy such as INC6000.

Description of FIGS. 12 and 13 In the embodiment of FIGS. 12 and 13, tumble (longitudinal vortex) of intake air is generated in the combustion chamber 1. Also in this embodiment, the relationship between the intake / exhaust valve and the two injection holes 21 and 22 is the same as in the case of FIG.
The tumble is rotated from the sub chamber 10 through the exhaust ports 4, 5,
The flow is such that it passes through the upper surface of the piston to the intake ports 2, 3. As a result, the two vortices 35 generated by the collapse of the tumble at the end of the compression stroke promote the flame expansion in the circumferential direction on the intake valve side of the outer peripheral edge of the combustion chamber.
In addition, it is preferable that the squish flow toward the center of the combustion chamber is not generated.

Description of FIG. 14 In the embodiment of FIG. 14, a protrusion 6a is formed on the top surface of the piston. This protrusion 6
The a can be elongated in the direction of the ridge line α, or can be formed in a substantially cylindrical shape extending in the direction of the cylinder axis. It is formed so as not to prevent jet flames from the injection holes 21 and 22 from reaching the outer peripheral edge of the combustion chamber. Due to the formation of the projections 6a, after the initial jet flame reaches the outer peripheral edge of the combustion chamber, the growth of the flame toward the center of the combustion chamber is suppressed (combustion rate suppression at the initial stage of combustion).

When the protrusion 6a is formed in a cylindrical shape,
The radius is r, the height distance between the top surface of the projection 6a and the injection holes 21 and 22 when the piston 6 is at the top dead center is L, and the angle between the injection holes 21 and 22 and the cylinder axis is θ. When
It is preferable to set the position of the sub chamber 10 so that tan θ≈r / L is satisfied. By setting in this way, it is preferable in obtaining the combustion in the present invention and sufficiently suppressing the growth of the flame toward the center of the combustion chamber.

When the protrusion 6a does not exist,
The angle θ is set within the range of 45 degrees to 60 degrees.
It is preferable for promoting the oxidation of unburned gas in the piston clevis that has flowed in during the compression stroke, and in this case, the initial jet flame is more likely than the piston upper wall (outer peripheral edge portion upper wall). It is considerably directed to the outer peripheral edge of the combustion chamber (the lower position of the inclined surfaces 1a and 1b in the case of the Pentorf type), which is also preferable in avoiding an increase in heat load on the piston. In order to avoid an increase in the heat load on the piston, the piston boss portion (the connecting portion of the piston pin) can be set so as to be positioned in the direction of the injection holes 21 and 22.

Description of FIG. 15 In the embodiment of FIG. 15, the positions of the injection holes 21 and 22 are slightly offset from the cylinder diametrical direction line passing through the center of the combustion chamber, and the injection holes 21 and 22 have the same offset direction. They are opposite each other. As a result, the collision angle of the jet flame from the injection holes 21, 22 with respect to the cylinder wall surface is relaxed, and flame growth in the circumferential direction of the combustion chamber is promoted. Further, when gas is introduced from the combustion chamber 1 into the sub-chamber 10, a swirl flow is generated in the sub-chamber 10 to improve scavenging property and turbulence in the sub-chamber 10, thereby improving ignitability. .

Description of FIGS. 16 and 17 In the embodiment of FIGS. 16 and 17, the directions of the two injection holes 21 and 22 are changed to those of FIG.
It has been changed slightly counterclockwise than the case. That is, the first injection hole 21 is directed to a position that is biased toward one intake port 2 side rather than the middle position between the two intake ports 2 and 3. Further, the second injection hole 22 is directed to a position deviated to one exhaust port 5 rather than the intermediate position between the two exhaust valves 4 and 5.

When the engine is in a high load condition where NO _X is a problem, intake air is supplied from both intake ports 2 and 3 to prevent swirling of intake air in the combustion chamber 1. . As a result, the initial jet flame is generated by the injection holes 21, 22.
The direction of the initial jet flame is directed so as to avoid the space between the two intake ports 2 and 3 where a large amount of the rich air-fuel mixture, particularly the liquid fuel, is likely to be directed in the same direction as in the direction of Suppress growth.

When the engine has a low load in which HC is a problem, for example, the supply of intake air from one intake port 2 is stopped, and as shown by the arrow in FIG.
Generates a swirl of intake air that goes to. This allows
The initial jet flame is changed by a swirl to reach the portion where the rich air-fuel mixture (liquid fuel) is present, so as to reduce HC. The directivity of the second injection hole 22 is changed in accordance with the change of the directivity of the first injection hole 21 (the first direction so that a ring-shaped flame surface is easily formed at the outer peripheral edge of the combustion chamber). The second injection hole 22 is located on the opposite side of the injection hole 21 by about 180 degrees). In addition, it is preferable to generate swirl at the time of a cold medium load in which a large amount of HC is discharged. The swirl generation and the generation stop can be switched by, for example, opening and closing an opening / closing valve provided in one intake port.

(3) Preferred embodiment of the present invention (FIGS. 18 to 39)

Increasing the amount of the air-fuel mixture flowing into the sub-chamber 10 promotes the internal pressure and temperature rise in the sub-chamber 10, and is preferable for improving the ignitability and the scavenging of the sub-chamber 10. Will be things. Further, increasing the initial combustion speed is preferable for increasing the speed of the initial jet flame and increasing the combustion effect at the outer peripheral edge of the combustion chamber. Of course,
Speed increases of late jet flames also increases the turbulence of the combustion field, Ah which is preferable for the HC reduction, NO _X reduction. For this reason, for example, it is preferable to retard the ignition timing so as to secure a long time for the air-fuel mixture to flow into the sub chamber 10 (so that the ignition timing for MBT is retarded). Further, for example, by using a variable valve timing mechanism, it is possible to quickly close the intake valve during cold, particularly during cold and low load, to increase the cylinder internal pressure and temperature.
As described above, FIG. 18 to FIG.
This will be described with reference to FIG.

Description of FIG. 18 In the embodiment of FIG. 18, the ignition gap 12a is sufficiently separated from the injection holes 21 and 22. As a result, the ignition gap 12a in the sub chamber 10
When the ignition is performed by the inside of the sub-chamber 10 near the injection holes 21 and 22, it receives a large pressure generated by the ignited flame before the flame in the sub-chamber 10 is ejected from the injection holes 21 and 22. The unburned air-fuel mixture is ejected from the injection holes 21 and 22 to promote the turbulence in the combustion chamber 1.

Description of FIG. 19 FIG. 19 shows the injection holes 21 and 22.
The axis of is offset with respect to the center of the sub chamber 12, and the jet flame itself ejected from the injection holes 21 and 22 is set to be a vortex flow. Then, a swirl of intake air is generated in a direction opposite to the vortex direction of the jet flame, and the combustion chamber 1
It is designed to promote internal disturbance.

Description of FIG. 20 FIG. 20 shows that the rich air-fuel mixture is unevenly distributed on the outer peripheral edge of the combustion chamber (the air-fuel ratio of the outer peripheral edge of the combustion chamber is richer than the air-fuel ratio of the central part of the combustion chamber). In this case, flame growth in the circumferential direction of the combustion chamber is promoted, and HC is reduced, especially when the load is low and H is low.
It is preferable for reducing C. It is preferable that the air-fuel ratio be as uniform as possible over the entire combustion chamber 1, especially when the load is high and the engine is warm, where NO _x is a problem. In order to change the distribution state of such an air-fuel mixture, for example, as the fuel injection valve 7, a fuel injection valve for enriching the outer peripheral edge of the combustion chamber and a fuel injection valve for the entire distribution of the combustion chamber may be prepared. .

Description of FIG. 21 In FIG. 21, an EGR port 8 is provided in the combustion chamber 1 so as to be oriented substantially tangentially to the combustion chamber 1 so that the high temperature EGR gas is unevenly distributed in the outer peripheral edge of the combustion chamber. . Due to the uneven distribution of EGR gas, it is preferable to form a swirl for intake air. The EGR port 8 is formed in the cylinder head SH in the form of a chamber, and
It is opened and closed by the EGR valve for opening and closing the GR port. The EGR valve is opened and closed twice in one cycle, the high temperature EGR gas is stored in the EGRP port (chamber) by the first opening, and the high temperature EGR gas stored by the second opening is stored. Discharge to combustion chamber 1. As a result, combustion is promoted at the outer peripheral edge of the combustion chamber, especially in cold when HC is a problem.

Considering the improvement of fuel efficiency, it is preferable that the ratio of the high temperature EGR gas (internal EGR gas) be 5% or more while keeping the air-fuel ratio lean at 20 or more. High temperature EGR
In order to use the internal EGR gas as the gas, for example, by using a variable valve timing mechanism, the exhaust valve closing timing is delayed to about 25 degrees after top dead center during cold, particularly during cold and low load. You can also

Description of FIGS. 22 and 23 FIGS. 22 and 23
In the outer peripheral edge of the combustion chamber, a spark plug 12B is separately provided in a region far from the directing region of the injection holes 21 and 22 and where ignition performance is particularly poor, so that ignition by the ignition gap 12a in the sub chamber 10 is performed. Prior to this, the ignition plug 12B is ignited. From the viewpoint of fuel consumption, it is preferable to limit the ignition using the spark plug 12B during the cold when the ignitability becomes a problem, particularly during the cold low load.

Description of FIG. 24 In the embodiment of FIG. 24, the directions of the two injection holes 21 and 22 into the sub chamber 10 are changed,
The gas supplied from the combustion chamber 1 through the injection holes 21 and 22 causes a vortex (longitudinal vortex) in the sub chamber 10 to increase the turbulence in the sub chamber 10. In this case, it is preferable that the injection holes 21 and 22 be as tangential to the inner surface of the sub chamber 10 as possible.
The directions of the vortices formed by 1 and 22 are the same as each other. In order to generate vortices in the sub chamber 10, it is preferable that the inner surface of the lower end portion of the sub chamber constituent member 11 be a smooth curved surface.

Description of FIG. 25 FIG. 25 is particularly preferable in a large displacement engine in which the cylinder diameter is large. That is, the second injection hole 2 facing the exhaust port direction
It is difficult for the jet flame from 2 to reach the outer peripheral edge of the combustion chamber on the side of the exhaust ports 4 and 5. Therefore, FIG.
Then, the sub chamber 10 itself is entirely offset to the exhaust port 4, 5 side with respect to the center of the combustion chamber 1. The opening area of the first injection hole 21 is smaller than the opening area of the second injection hole 22. As a result, the intake port 2,
The jet flame can surely reach not only the No. 3 side but also the outer peripheral edge of the combustion chamber on the exhaust ports 4, 5 side where the jet flame is hard to reach. In addition to the above, the sub-chamber 10
Alternatively, the spark plug 12 may have a large diameter (for example, the spark plug 12 is M16).

Description of FIGS. 26 and 27 In order to favorably introduce unburned gas and radicals into the sub chamber 10, the injection holes 21,
It is preferable to improve the flow velocity in the periphery of 22. Therefore, a swirl having a swirl center at an eccentric position is generated in the combustion chamber 1 with respect to the sub chamber 10 provided substantially in the center of the combustion chamber 1.
It may be formed inside, and for this purpose, an oblique swirl in which the swirl and the tumble are combined is formed. 26 and 27, the size of the arrow indicates the size of the flow velocity. Further, in order to sufficiently increase the flow velocity around the injection holes 21 and 22 with a normal swirl instead of an oblique swirl, it is preferable to set the swirl ratio to 2.5 or more. It is preferable that the fuel ratio is leaner than 20. Further, it is also possible to form a concave portion on the top surface of the piston and increase the angular momentum of the intake air by pushing the unburned air-fuel mixture into the concave portion.

Description of FIGS. 28 and 29 In the embodiment of FIGS. 28 and 29, the injection hole 21 is
The injection port 22 is directed to a substantially intermediate position between the one intake port 2 and the exhaust port 4 adjacent to the intake port 2, and the injection hole 22 is provided in the other intake port 3 and the intake port 3. It is directed to a substantially intermediate position between the adjacent exhaust ports 5. Further, the intake air is supplied from the two intake ports 2 and 3 to generate tumble in the combustion chamber 1. This tumble has two injection holes 21 and 2 when viewed from the cylinder axis direction.
It is considered to be a vortex in the direction of turning around a straight line connecting the two. As a result, near the collapse of the tumble,
A vortex that is substantially orthogonal to the directivity line of the injection holes 21 and 22 is generated along the inclined surface 1a of the F-shaped combustion chamber,
The introduction of unburned gas into the sub chamber 10 through 22 is promoted.

Description of FIGS. 30 to 32 In the embodiment of FIGS. 30 to 32, communication holes 41 and 42 are formed in the sub chamber 10 between the two injection holes 21 and 22, respectively.
The communication ports 41, 42 do not allow the initial jet flame generated by the ignition by the ignition gap 12a to pass (extinguish the flame), but allow only the latter jet flame generated by the self-ignition in the sub chamber 10 to pass. is there. That is, when the initial jet flame is relatively cold, the flame is extinguished when passing through the communication ports 41 and 42,
The initial jet flame is ejected only from the injection holes 21 and 22 as shown in FIG. At the time of self-ignition in the sub-chamber 10, which has a relatively high temperature, the secondary jet flame is not extinguished by the communication ports 41, 42, and the late jet flame is communicated in addition to the injection holes 21, 22 as shown in FIG. It is also jetted from the mouths 41 and 42.

By providing such communication ports 41, 42, the gas can be introduced into the sub-chamber 10 more favorably, and both the ignition by the ignition gap 12a and the self-ignition in the sub-chamber 10 can be achieved. Will be improved together. Further, the setting of the communication ports 41 and 42 for performing the above-mentioned function is a / when the surface area of the communication port 41 is acm ² and the volume of the sub chamber 10 is Vcm ^3.
V (1 / cm) is 1.25 × 10 ^{−3 to} 3.0 × 10
^It should be set within the range of ^-3 .

Description of FIGS. 33 to 38 In the embodiment of FIGS. 33 to 38, the interior of the sub-chamber 10 is made into two chambers, and gas is passed between these two chambers to allow self-ignitability in the sub-chamber 10. And so on. That is, the inside of the sub-chamber 10 is divided into the first chamber 51 and the second chamber 52 by the partition wall 50. The ignition gap 12 a is located in the first chamber 51, and the injection holes 21 and 22 are opened. Partition wall 5
A communication port 53 is formed at 0, and the two chambers 51 and 52 are communicated by this communication port 53. When the surface area of the communication port 53 is acm ² and the volume of the sub chamber 10 is Vcm ³ , a / V (1 / cm) is 1.25 × 10 ^{−3 to} 3.
The range is set to 0 × 10 ^-3 (Fig. 3
0 to 32 correspond to the communication ports 41 and 42).

The operation of the second chamber 52 and the communication port 53 is as shown in FIGS. 34 to 38. That is, the first chamber 5
When ignition is performed by the ignition gap 12a at 1,
Initially, the unburned gas is jetted from the injection holes 21 and 22 into the combustion chamber 1, and the unburned gas is also introduced into the second chamber 52 (FIG. 34). Thereafter, the initial jet flame is ejected from the injection holes 21 and 22 (FIG. 35), but the jet flame is not ejected to the second chamber 53 due to the quenching at the communication port 53, and the radicals are introduced to the second chamber 53. The inside of the chamber 52 is activated (FIG. 36).

As the pressure temperature in the combustion chamber 1 rises due to the ejection of the initial jet flame into the combustion chamber 1, the second chamber 5
The activation of No. 2 progresses further, and eventually the second chamber 52 is self-ignited. During self-ignition in the second chamber 52, the combustion chamber 1
Since the temperature and pressure in the first chamber 51 and the second chamber 52 are also considerably high, the flame generated by self-ignition in the second chamber 52 is ejected to the first chamber 51 without being extinguished at the communication port 53. (FIG. 37). And finally, from the first chamber 51 to the injection hole 2
A late jet flame is ejected into the combustion chamber 1 through Nos. 1 and 22 (FIG. 38).

Description of FIG. 39 FIG. 39 shows the second chamber 52 of the sub chamber 10 in FIGS.
The first chamber 51 is formed in the same manner as that shown in FIG. 2, instead of being formed in the cylinder head SH. The communication port 53 that connects the first chamber 51 and the second chamber 52 is formed in the side wall portion of the sub chamber constituent member 11. Further, in the embodiment, the second chamber 52
A plurality of (two) are provided. By doing so, the volume of the second chamber 52 is ensured to be large,
Generation of late jet flame is sufficiently promoted.

(4) Preferred embodiment of the present invention (FIGS. 40 to 43)

Description of FIG. 40 In FIG. 40, the sub chamber constituent member 11 is screwed into a spark plug mounting screw portion formed on the cylinder head SH in a normal engine, and the flange portion 11b of the sub chamber constituent member 11 is screwed. Is seated on the spark plug mounting seat 61, and the combustion chamber 1 of the sub chamber constituent member 11 is
In order to minimize the amount of protrusion to the combustion chamber 1, that is, only the injection holes 21 and 22 and the vicinity thereof are projected into the combustion chamber 1. Further, since the space above the spark plug mounting seat 61, that is, the spark plug mounting hole 60 is open to the engine room, the air introduced therein radiates the spark plug 12 and the sub chamber constituent member 11 sufficiently. I am doing it.

Description of FIG. 41 In the embodiment of FIG. 41, the sub-chamber constituting member 11 has a two-layer structure of an outer layer constituting member 11A and an inner layer constituting member 11B. Then, the outer layer constituting member 11A is made of a material (for example, an aluminum alloy) having a high heat transfer coefficient with the cylinder head SH (for example, an aluminum alloy), while the inner layer constituting member 11B is made of a material. The material having a small heat transfer coefficient (for example, carbon steel) is used.

By using a member having a small specific heat (for example, an aluminum alloy) as the inner layer constituting member 11B, it is possible to improve the ignitability at the cold start. Further, the inner layer constituent member 11B may be composed of a catalyst having a combustion promoting effect (for example, Pt, Rd, etc.). In this case,
The inner layer constituent member 11B may be formed as a coating layer.

Description of FIG. 42 In the embodiment of FIG. 42, a cooling water system passage 70 is formed in the cylinder head SH in the vicinity of the sub-chamber 10 (sub-chamber constituent member 11) so as to surround the sub-chamber SH, so that the sub-heat chamber is easily overheated. The chamber 10 and the ignition gap 12a are sufficiently cooled.

Description of FIG. 43 In the embodiment of FIG. 43, the cooling system passage of the entire engine is devised so that both cooling and heating of the cylinder head SH, that is, the sub chamber 10 are satisfied. That is, the cooling water supply system passage 76 from (the outlet of) the radiator 75 is branched into two on the way, one branch supply system passage 76a is connected to the cylinder block 77, and the other branch supply system passage 76b is connected to the cylinder. Head SH
(Corresponding to the cooling water passage 70 in FIG. 42). A cooling water discharge system passage 78a from the cylinder block 77 and a cooling water discharge system passage 78b from the cylinder head SH are joined together by a common discharge system passage 78 and are connected to the radiator 75 (the entrance thereof). In the branch supply system path 76b,
An electromagnetic type flow control valve 79 is connected.

Now, when the engine is warm, especially when the engine is under heavy load, the valve 79 is fully opened. As a result, the low-temperature cooling water from the radiator 75 is transferred to the cylinder block 7
The sub-chamber 10 is sufficiently cooled by being supplied to the cylinder head SH from the branch supply system path 76b without passing through 7.

The valve 79 is fully closed when the engine is cold, especially when the load is low. As a result, the supply of cold cooling water to the cylinder head SH is stopped, and the ignition performance in the sub chamber 10 is prevented from being impaired. It should be noted that the valve 79 is not a two-stage switch between fully open and fully closed, but is, for example,
The flow rate ratio of the cooling water supply system passage 76b to the cooling water supply system passage 76a can be changed in multiple stages of three or more stages or continuously variably according to the engine load and the engine temperature.

(5) Supplementary explanation

Here, the ignition gap 12 in the sub chamber 10
By utilizing a, it is possible to more reliably generate the late jet flame. That is, the first ignition may be performed at the normal ignition timing to generate the initial jet flame, and then the second ignition may be performed at the timing at which the self-ignition in the sub chamber 10 is performed. Comparison of NO _X generation time

In the present invention, at least when the load is low,
It is preferable to increase the internal EGR gas, swirl the intake air, and make the air-fuel ratio lean, especially when the load is cold and low. That is, the fuel efficiency is improved by making the air-fuel ratio lean, and the late jet flame is generated (sub chamber 1
It is preferable for surely obtaining (self-ignition at 0). In addition, the swirl of the intake air is preferable for advancing leanness while favorably introducing the air-fuel mixture in the sub chamber 10. Furthermore, by performing internal EGR,
Compared with the case where external EGR is performed, the fuel consumption is improved without lowering the isovolume.

Compared with a normal engine having only a spark plug in the substantial center of the combustion chamber, the fuel consumption is improved by 10% or more, and NO is improved.
_{When the X} reduction ratio is 75% or more, the internal EGR ratio may be 5% or more and the swirl ratio may be 2.5 or more. At this time, the lean limit of the air-fuel ratio becomes a value close to 24. (When the air-fuel ratio becomes 20 or more, the leaner the CO reduction rate, the leaner it becomes).

Although the embodiments have been described above, the present invention is not limited to this, and includes the following cases, for example.

The number of injection holes (21, 22) may be one or three or more. When a plurality of injection holes are provided, particularly when three or more injection holes are provided, the injection holes can be formed at substantially equal intervals in the circumferential direction of the combustion chamber. You may make it differ greatly.

The number of intake ports (intake valves) and exhaust ports (exhaust valves) is, for example, one intake port and one exhaust port, or three intake ports. Therefore, the number of exhaust ports can be appropriately set to two, etc.

The shape of the combustion chamber is not limited to the Pentorf type,
It can be formed in an appropriate shape such as a hemispherical shape or a wedge shape. In the claims, the claims in the combustion control method can be applied as a combustion control device, and conversely, the claims in the combustion control device can be applied as a combustion control method. The terminology used in each of the embodiments and the like can be superordinated to the name or function of the member by adding the name of means or device. In addition, in the embodiments and the like, a combination of two or more can be conceptualized as a plural term.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a simplified plan view of a combustion chamber as seen from the inner surface side thereof, showing an initial combustion state.

FIG. 2 is a sectional view corresponding to line X2-X2 in FIG.

FIG. 3 is a diagram corresponding to FIG. 1, showing a mid-stage combustion state.

FIG. 4 is a diagram corresponding to FIG. 2, showing a mid-stage combustion state.

FIG. 5 is a diagram corresponding to FIG. 1, showing a latter stage state of combustion.

FIG. 6 is a diagram corresponding to FIG. 2, showing a latter stage state of combustion.

FIG. 7 is a view showing a combustion mode according to the present invention in comparison with a conventional one.

FIG. 8 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 9 is a sectional view of an essential part showing a modified example of the present invention.

FIG. 10 is a sectional view of an essential part showing a modified example of the present invention.

11 is a cross-sectional view of a main part before the state of FIG. 10 is obtained.

FIG. 12 is a sectional view of an essential part showing a modified example of the present invention.

13 is a simplified plan view corresponding to FIG.

FIG. 14 is a sectional view of an essential part showing a modified example of the present invention.

FIG. 15 is a simplified plan view showing a modified example of the present invention.

FIG. 16 is a simplified plan view showing a modified example of the present invention.

FIG. 17 is a simplified plan view showing a modified example of the present invention.

FIG. 18 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 19 is a simplified plan view showing a modified example of the present invention.

FIG. 20 is a simplified plan view showing a modified example of the present invention.

FIG. 21 is a simplified plan view showing a modified example of the present invention.

FIG. 22 is a simplified plan view showing a modified example of the present invention.

23 is a diagram showing the ignition timing of the outer periphery spark plug shown in FIG. 23.

FIG. 24 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 25 is a simplified plan view showing a modified example of the present invention.

FIG. 26 is a simplified plan view showing a modified example of the present invention.

FIG. 27 is a simplified plan view showing a modified example of the present invention.

FIG. 28 is a simplified plan view showing a modified example of the present invention.

FIG. 29 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 30 is a simplified plan view showing a modified example of the present invention.

FIG. 31 is a simplified plan view showing a modified example of the present invention.

FIG. 32 is a simplified plan view showing a modified example of the present invention.

FIG. 33 is a cross-sectional view of essential parts showing a modified example of the present invention.

34 is a cross-sectional view of the main parts showing the combustion mode in FIG. 33.

FIG. 35 is a cross-sectional view of the essential parts showing the combustion mode in FIG. 33.

FIG. 36 is a cross-sectional view of the essential parts showing the combustion mode in FIG. 33.

FIG. 37 is a cross-sectional view of the essential parts showing the combustion mode in FIG. 33.

FIG. 38 is a cross-sectional view of the essential parts showing the combustion mode in FIG. 33.

FIG. 39 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 40 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 41 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 42 is a cross-sectional view of essential parts showing a modified example of the present invention.

FIG. 43 is a cooling water system diagram showing a modified example of the present invention.

[Description of sign]

 SH: Cylinder head 1: Combustion chamber 2, 3: Intake port 4, 5: Exhaust port 6: Piston 6a: Protrusion 8: EGR port 10: Subchamber 11: Subchamber constituent member 12: Spark plug 12a : Ignition gap 12b: Threaded portion of spark plug 12B: Spark plugs 21 and 22 provided on the outer peripheral edge of the combustion chamber 33: Injection hole 33: Sub-chamber constituent member 34: Cooling water passage 41, 42: Communication port 50: Partition wall 51: No. 1st chamber 52: Second chamber 53: Communication port 70: Cooling water passage 75: Radiator 76a: Cooling water supply system passage (for cylinder block) 76b: Cooling water supply system passage (for cylinder head) 79: Flow rate adjusting valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F02B 23/00 F02B 23/00 G 23/08 23/08 ASH F02F 1/24 F02F 1 / 24 E F02M 25/07 580 F02M 25/07 580C F02P 13/00 302 F02P 13/00 302B 15/08 301 15/08 301M

Claims (49)

[Claims] 1. A sub-chamber having an injection hole directed to the outer peripheral edge of the combustion chamber and having an ignition gap inside is disposed, and an air-fuel mixture in the sub-chamber is ignited by the ignition gap, and inside the sub-chamber. The first step of ejecting the generated flame from the injection hole toward the outer peripheral edge of the combustion chamber, the second step of introducing the unburned air-fuel mixture in the combustion chamber into the sub chamber, and the unburned gas introduced into the sub chamber And a third step of causing a mixture to self-ignite in the sub chamber and ejecting a flame from the injection hole. 2. The method according to claim 1, wherein before ignition by the ignition gap in the first step,
The air-fuel mixture supplied to the combustion chamber is introduced into the sub chamber through the injection holes, and the pressure in the combustion chamber becomes higher than the pressure in the sub chamber due to the ejection of flame toward the outer peripheral edge of the combustion chamber in the first step. As a result, the unburnt air-fuel mixture in the combustion chamber is introduced into the sub chamber, and the combustion control method for the engine. 3. The sub-chamber according to claim 1, wherein the sub-chamber is arranged substantially at the center of the combustion chamber, and the plurality of injection holes are provided at intervals in the circumferential direction of the combustion chamber. Engine combustion control method. 4. The third step according to claim 3, wherein the flame ejected toward the outer peripheral edge of the combustion chamber in the first step causes the flame to grow over substantially the entire circumferential direction of the combustion chamber, and then the third step. thing. 5. The injection hole according to claim 3, wherein some of the plurality of injection holes are directed in a direction in which the intake valve is arranged, as viewed from the cylinder axis direction. 6. The intake system according to claim 5, further comprising two intake valves arranged in parallel with each other, wherein the part of the injection holes is provided with the two intake valves when viewed from a cylinder axis direction.
It is directed toward the outer peripheral edge of the combustion chamber through the space between two intake valves. 7. The intake air swirl according to claim 1, wherein a swirl of intake air is generated in the combustion chamber. 8. The high temperature EGR gas is introduced into the combustion chamber according to claim 1. 9. The air-fuel ratio of the air-fuel mixture supplied to the combustion chamber is sufficiently leaner than the stoichiometric air-fuel ratio, at least at a low load. 10. A sub-chamber having an injection hole directed to the outer peripheral edge of the combustion chamber and having an ignition gap therein is set, and the setting of the sub-chamber and the injection hole is performed by setting the air-fuel mixture in the sub-chamber to the After the initial combustion in which the flame generated in the sub chamber is ejected from the injection hole toward the outer peripheral edge of the combustion chamber by igniting by the ignition gap,
The engine is characterized in that the unburned air-fuel mixture in the combustion chamber introduced into the sub chamber is self-ignited in the sub chamber so that the flame is ejected again from the injection hole to perform the late combustion. Combustion control device. 11. A fuel supply means for supplying fuel to a combustion chamber through an intake port according to claim 10, wherein the air-fuel mixture is supplied to the auxiliary chamber before the initial combustion is performed from the combustion chamber. A combustion control device for an engine, which is performed through a hole. 12. The sub-chamber according to claim 10, wherein the sub-chamber is provided substantially in the center of the combustion chamber, the plurality of injection holes are provided at intervals in the circumferential direction of the combustion chamber, and are jetted toward the outer peripheral edge of the combustion chamber. A combustion control device for an engine, characterized in that self-ignition is performed in the sub chamber after the flame has grown over substantially the entire length in the circumferential direction of the combustion chamber due to the flame. 13. The engine according to claim 12, wherein some of the plurality of injection holes are oriented in the intake valve installation direction when viewed from the cylinder axis direction. Combustion control device. 14. The method of claim 10, Acm ² the surface area of the injection hole, the volume of the auxiliary chamber Vcm
³ , when A / V (1 / cm) is 3.0 × 1
A combustion control device for an engine, wherein the combustion control device is set so as to fall within a range of 0 ^{−3 to} 1.5 × 10 ⁻² . 15. In claim 10, when the surface area of the injection holes is Acm ² , the number of injection holes is n, and the volume of the sub chamber is Vcm ³ , A · n / V is (1 / cm ) Is 7.5 × 10 ^{−3 to} 3.
A combustion control device for an engine, characterized in that the range is set to 0 × 10 ^-2 . 16. The combustion control system for an engine according to claim 14, wherein the volume V of the sub chamber is set to be less than 1.0 cm ³ when the cylinder bore diameter is less than 83 mm. 17. The combustion control system for an engine according to claim 14, wherein when the cylinder bore diameter is less than 83 mm, the length L of the injection hole is set to be less than 2.8 mm. 18. The combustion control system for an engine according to claim 14, wherein the volume V of the sub chamber is set to 1.0 cm ³ or more when the cylinder bore diameter is 83 mm or more. 19. The combustion control device for an engine according to claim 14, wherein when the cylinder bore diameter is 83 mm or more, the length L of the injection hole is set to be 2.8 mm or more. 20. The sub chamber constituent member according to claim 10, wherein the sub chamber constituent member is fixed to the spark plug so as to surround the ignition gap and in which the injection hole is formed. A combustion control device for an engine, characterized in that a chamber is configured, and the sub chamber constituent member has a screw portion for attachment to a cylinder head. 21. The sub-chamber constituting member, wherein the injection hole is formed and the screw portion for mounting the ignition plug is formed, is fixed to a cylinder head, and the ignition plug is constituted by the sub-chamber structure. A combustion control device for an engine, characterized in that the sub chamber is defined by the sub chamber constituent member and the ignition plug when the sub chamber is screwed to the member. 22. The combustion control device for an engine according to claim 10, wherein the sub chamber is integrally formed with a cylinder head. 23. The engine combustion control device according to claim 10, wherein only the injection hole and a portion in the vicinity of the injection hole of the sub chamber are exposed in the combustion chamber. 24. The engine combustion control device according to claim 10, wherein the member forming the sub chamber is cast around a cylinder head. 25. The intake valve according to claim 10, wherein an intake valve is provided on one side in the diametrical direction of the cylinder and an exhaust valve is provided on the other side, and a means for generating a tumble of the intake is provided. The flow direction of the tumble is set so that it flows to the intake valve after passing through the exhaust valve and the upper surface of the piston.
A combustion control device for an engine, characterized in that 26. The sub-chamber according to claim 10, wherein the sub-chamber is located substantially in the center of the combustion chamber, and a protrusion portion is formed on the top surface of the piston for restricting flame propagation from the outer peripheral edge portion of the combustion chamber to the center of the combustion chamber. A combustion control device for an engine, characterized in that 27. The directing direction of the injection hole according to claim 10, wherein the direction of the injection hole is set so as to avoid a region where the rich air-fuel mixture exists in the outer peripheral edge portion of the combustion chamber, and the injection direction is set only when the load is low. A combustion control device for an engine, comprising: a swirl generating means for generating a swirl of intake air so that a flame to be deflected to the rich air-fuel mixture region. 28. The sub chamber, that is, the injection hole is located substantially at the center of the combustion chamber, and the axis of the injection hole is 45 degrees to 6 degrees with respect to the cylinder axis.
A combustion control device for an engine, wherein the combustion control device is set to have an angle range of 0 degree. 29. The sub chamber, that is, the injection hole is located substantially at the center of the combustion chamber, and the plurality of injection holes are provided at intervals in the circumferential direction of the combustion chamber. Is offset with respect to a cylinder diametrical line passing through the center of the combustion chamber. 30. The air-fuel mixture in the sub chamber is ignited by an ignition plug according to claim 10,
Before the flame is ejected from the injection hole, the compressed air-fuel mixture in the sub chamber compressed by the ignited flame is set to be ejected from the injection hole. Combustion control device. 31. The engine combustion control device according to claim 30, wherein the compressed air-fuel mixture is ejected from the sub chamber by increasing the distance between the injection hole and the ignition gap. . 32. The internal EGR for increasing the internal EGR gas in the combustion chamber according to claim 10.
An engine combustion control device comprising an increasing means. 33. The engine combustion control device according to claim 32, wherein the supply ratio of the internal EGR gas is 5% or more. 34. The combustion control device for an engine as claimed in claim 32 or 33, wherein the internal EGR gas is eccentrically supplied to an outer peripheral edge portion of the combustion chamber. 35. When the engine is cold, the rich air-fuel mixture is supplied so as to be unevenly distributed on the outer peripheral edge of the combustion chamber, and when the engine is warm, the rich air-fuel mixture has a substantially uniform concentration. An engine combustion control device, characterized in that the mixture is set to be supplied. 36. A spark plug is provided separately in a region of the outer peripheral edge of the combustion chamber, which is outside the directivity region of the injection hole and in which the ignitability deteriorates. 37. The injection hole according to claim 10, wherein the injection hole has a plurality of holes, and the introduction gas introduced into the sub chamber from the combustion chamber through the injection holes becomes a vortex in the sub chamber. A combustion control device for an engine, wherein: 38. The sub chamber is offset from the combustion chamber center so as to be closer to the exhaust valve than the intake valve when viewed from the cylinder axis direction, and the injection hole is When viewed from the cylinder axis direction, it has a first injection hole oriented in the intake valve direction and a second injection hole oriented in the exhaust valve direction, and the opening area of the first injection hole is the second injection hole. An engine combustion control device, characterized in that the opening area is larger than the opening area of the hole. 39. The sub-chamber is located substantially at the center of the combustion chamber according to claim 10, and an intake air swirl having a swirl ratio of 2.5 or more is generated in the combustion chamber and supplied to the combustion chamber. The combustion control device for an engine, wherein the air-fuel ratio of the air-fuel mixture is set to 20 or more. 40. The combustion control device for an engine according to claim 10, wherein the sub chamber is located substantially in the center of the combustion chamber, and an oblique swirl is generated in the combustion chamber. 41. The sub-chamber is located substantially in the center of the combustion chamber, intake air tumble is generated in the combustion chamber, and the direction of the injection hole is such that the tumble flow is near the piston top dead center. A combustion control device for an engine, wherein the combustion control device is set so as to be substantially orthogonal to the direction. 42. A communication port according to claim 10, further comprising a communication port communicating with the sub chamber and the combustion chamber at a position different from the injection hole, the communication port being ignited in the sub chamber by the spark plug. A combustion control device for an engine, wherein a shape of the initial combustion flame is set so as not to be ejected toward the combustion chamber. 43. The communication port according to claim 42, wherein the communication port is set so as to eject the flame of late combustion due to self-ignition in the sub chamber to the combustion chamber through the communication port. Engine combustion control device. 44. claimed in claim 43, wherein the acm ² the surface area of the communication port, the sub-chamber volume Vcm ²
Then, a / V is (1 / cm), 1.25 × 10 ^{−3 to} 3.0 ×
A combustion control device for an engine, wherein the combustion control device is set to fall within a range of 10 ⁻³ . 45. The engine combustion control device according to claim 10, wherein the inner surface of the sub chamber is coated with a catalyst for promoting combustion. 46. The engine combustion control device according to claim 10, wherein the spark plug is reignited immediately before the start of the latter combustion. 47. The first chamber, wherein the sub chamber has the injection hole and the ignition gap is located, and the second chamber communicates with the first chamber through a communication port. A chamber, wherein the communication inner port prevents the flame of the initial combustion ignited in the first chamber by the spark plug from being ejected to the second chamber, and the latter stage of self-ignition in the second chamber. It is set to eject a combustion flame toward the first chamber,
A combustion control device for an engine, characterized in that 48. The in-head cooling water passage formed in the cylinder head according to claim 10,
It has a sub-chamber cooling passage located near the sub-chamber, and serves as a cooling water supply system passage for supplying the cooling water from the radiator to the engine, and is separate from the block supply passage connected to the cooling water passage in the cylinder block. Independently, a head supply passage communicating with the head cooling water passage is provided, and the cooling water supply amount adjusting means increases the amount of cooling water supplied from the head supply passage when the engine is warm as compared to when it is cold. A combustion control device for an engine, comprising: 49. The sub-chamber according to claim 10, wherein only one sub-chamber is provided substantially in the center of the combustion chamber, and the injection holes are provided with two first injection holes and two second injection holes. A combustion control device for an engine, wherein one injection hole is directed toward the intake valve in the outer peripheral edge of the combustion chamber, and the second injection hole is directed toward the exhaust valve in the outer peripheral edge of the combustion chamber. .