JPH06137233A - Assist air type fuel injection device - Google Patents

Abstract

PURPOSE:To stably burn air-fuel mixture even at the time of lean burn control by distributing and injecting fuel together with supercharging assist air from a single injector to a sub-combustion chamber and a main combustion chamber. CONSTITUTION:A holding cylinder 11 for an injector 3 and a partition wall member 10 having a plug fitting part 12 are provided between a cylinder head 2 and an injector 3, and a sub-combustion chamber 1 communicated with the main combustion chamber 2A side through a communicating hole 11B1 is formed in the holding cylinder 11. A distribution nozzle 13 provided with a main nozzle part 13D elongated to a communicating hole 11B1 of the base 11B and a distribution hole 13E is disposed in the holding cylinder 11. Fuel jetted together with supercharging assist air from the injection nozzle 4B of the injector 3 is distributed and supplied to the main combustion chamber 2A side and the stub- combustion chamber C side, air-fuel mixture liable to become rich in the sub- combustion chamber C is ignited by a spark plug 15, and cylindrical flame (f) is jetted into the main combustion chamber 2A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assist air type fuel injection device which is preferably used for supplying fuel into a cylinder of an automobile engine in a state of being atomized by assist air. The present invention relates to an assist air type fuel injection device that uses an injection type fuel injector.

[0002]

2. Description of the Related Art Generally, a main injector is provided on the intake port side of a cylinder head, and a sub combustion chamber communicating with the main combustion chamber and having a smaller volume than the main combustion chamber is provided on the cylinder head side. There is known an internal combustion engine in which an in-cylinder direct injection sub-injector and an ignition plug are provided.

In this type of internal combustion engine, the lean fuel-air mixture is sucked into the main combustion chamber, and the fuel is injected from the sub-injector into the sub-combustion chamber so as to generate a fuel-air mixture having an appropriate concentration for ignition by a spark plug. Is injected into the main combustion chamber to burn the flame produced by igniting the fuel in the auxiliary combustion chamber to burn the lean air-fuel mixture in the main combustion chamber to purify exhaust gas and improve fuel efficiency. .

In this case, since the cylinder head is provided with the sub-injector together with the main injector, the number of components of the entire fuel injection device increases, and the injection amount of each injector is individually calculated by the fuel injection control device. Therefore, there is a problem that the control process becomes complicated.

Therefore, the present applicant has previously filed Japanese Patent Application No. 4-114.
No. 142 (hereinafter referred to as "prior art"), in a cylinder head of an engine body, a combustion chamber is defined between a main combustion chamber on the cylinder side and a sub combustion chamber on the injector side, the combustion chamber being located between the main combustion chamber and the injector. A partition member having a communication hole for communicating the combustion chamber with the main combustion chamber is provided, and the partition member has
A part of the fuel ejected from the injector together with the supercharging assist air is distributed into the sub combustion chamber, and the remaining fuel is discharged together with the supercharging assist air into the main combustion chamber through the communication hole; Assist air type fuel provided with a spark plug that distributes and discharges supercharged assist air and fuel that are distributed and jetted into the sub-combustion chamber by a distribution nozzle to jet a flame into the main combustion chamber from the communication hole. An injector was proposed.

According to the above-mentioned prior art, the fuel jetted together with the supercharging assist air from the injector is distributed and supplied to the combustion chamber side and the auxiliary combustion chamber side by the distribution nozzle provided in the partition wall member, and the auxiliary combustion chamber is supplied. A rich mixture is generated in the main combustion chamber so that it can be easily ignited, and a lean mixture is generated in the main combustion chamber. Then, the mixture in the sub-combustion chamber is ignited by the spark plug, and the generated flame is ejected into the main combustion chamber,
With this flame, the lean air-fuel mixture in the main combustion chamber is surely burned, so that stable lean burn control and the like can be performed.

[0007]

However, in the above prior art, since the flame ejected from the communicating hole of the partition wall member into the main combustion chamber has a solid columnar shape or a conical shape, the flame and the lean combustion inside the main combustion chamber. However, there is an unsolved problem that it is difficult to sufficiently increase the contact area with the air-fuel mixture and it is difficult to sufficiently improve the combustion efficiency of the air-fuel mixture in the main combustion chamber.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention distributes and supplies fuel together with supercharging assist air from a single injector to the sub-combustion chamber and the main combustion chamber to supply the fuel. By igniting the air-fuel mixture, the contact area between the flame ejected from the auxiliary combustion chamber to the main combustion chamber and the air-fuel mixture in the main combustion chamber can be increased, and the lean air-fuel mixture in the main combustion chamber can be efficiently burned. It is an object of the present invention to provide an assist air type fuel injection device as described above.

[0009]

In order to solve the above-mentioned problems, the present invention is characterized in that the cylinder head of the engine body is located between the injector and the combustion chamber and the main combustion chamber on the cylinder side is located. And a sub-combustion chamber on the injector side, and a partition member having a communication hole for communicating the sub-combustion chamber with the main combustion chamber is provided, and the partition member is provided with a supercharge assist air from the air chamber side. And a distribution nozzle having a distribution hole for distributing a part of the fuel ejected together with the auxiliary combustion chamber, and a main nozzle portion for discharging the remaining fuel together with the supercharging assist air to the main combustion chamber, and the distribution nozzle. An ignition plug is provided which burns the fuel and supercharge assist air distributed and ejected from the holes into the sub-combustion chamber and ejects the flame from the communication hole toward the main combustion chamber. The main nozzle part Serial is extended from the air chamber side in a position axially to the communication hole of the partition member in that formed in the tubular by.

Further, the distribution hole of the distribution nozzle may be formed so as to open into the auxiliary combustion chamber at a position separated from the ignition plug in the circumferential direction of the auxiliary combustion chamber.

[0011]

With the above structure, the flame generated by igniting the air-fuel mixture in the auxiliary combustion chamber is injected into the main combustion chamber from between the communication hole of the partition wall member and the main nozzle portion into a cylindrical or hollow conical shape. The lean air-fuel mixture in the main combustion chamber can be contacted with a large area to surely burn the air-fuel mixture.

Further, the main nozzle portion of the distribution nozzle is heated from the outside by the combustion of the air-fuel mixture in the auxiliary combustion chamber, and the fuel injected from the main nozzle portion toward the main combustion chamber is vaporized and diluted in the main combustion chamber. It can be in a state suitable for causing combustion.

Further, if the distribution hole of the distribution nozzle is formed so as to open into the auxiliary combustion chamber at a position separated from the ignition plug in the circumferential direction of the auxiliary combustion chamber, the fuel is discharged from the distribution hole of the distribution nozzle toward the ignition plug. Is no longer directly injected with the assist air, and this fuel spreads uniformly in the auxiliary combustion chamber together with the assist air, so there is no partial difference in fuel concentration in the air-fuel mixture in the auxiliary combustion chamber. It is possible to ignite with a spark plug surely.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

First, FIGS. 1 and 2 show a first embodiment of the present invention.

In the figure, 1 is an engine body, 2 is a cylinder head constituting the upper part of the engine body 1, a main combustion chamber 2A is defined inside the cylinder head 2, and the cylinder head 2 has a main combustion chamber 2A. Outside of engine body 1 and main combustion chamber 2
A mounting hole 2B communicating with A is provided.

Reference numeral 3 denotes an in-cylinder direct injection type injector which is mounted in a mounting hole 2B of the cylinder head 2 through a partition member 10 which will be described later. The injector 3 is generally composed of an injector body 4 and a cover 5 which will be described later. It is configured. Here, the injector body 4 is a casing 4A.
An electromagnetic actuator (not shown) is built into the inside of the nozzle, and the needle valve 4C is opened and closed in the injection nozzle 4B provided on the tip side of the casing 4A by the electromagnetic actuator. In addition, a cylindrical connection port 4D and a connector 4E are provided on the base end side of the casing 4A,
A fuel pipe is connected to the connection port 4D, and a lead wire (not shown) is provided on the output side of the control unit for the connector 4E.
And the like. Then, the injector body 4 opens and closes the needle valve 4C based on a signal from the control unit, and injects fuel from the injection nozzle 4B. Here, the fuel injection amount is set so that the mixture of air and fuel sucked into the main combustion chamber 2A from the outside has a predetermined air-fuel ratio.

Reference numeral 5 is an injection nozzle 4B of the injector body 4.
The cover 5 is fixed to the front end side of the cover 5. The cover 5 is composed of a cylindrical member 6 and a valve seat member 7, which will be described later, in a cylindrical shape with a bottom, and an air chamber A is defined inside the cover 5. It has become so.

Reference numeral 6 denotes a tubular member which constitutes the cover 5, and the tubular member 6 has a fitting portion whose inner peripheral side at the upper end is fitted and fixed to the injection nozzle 4B of the injector body 4 as shown in FIG. 6A, and the female screw 13 of the large-diameter cylindrical portion 13A of the distribution nozzle 13, which will be described later, is provided on the outer peripheral side of the distal end portion of the cylindrical member 6.
A screw portion 6B that is screwed into A1 is formed. And
A plurality of vent holes 6C, 6C, ... Are formed in the tubular member 6 in the middle of the fitting portion 6A and the screw portion 6B.
Here, each vent hole 6C is bored from the outer peripheral surface side of the tubular member 6 toward the tangential direction of the inner peripheral surface, and jets supercharging assist air, which will be described later, into the air chamber A in a swirling flow state. It is like this.

Reference numeral 7 denotes a state in which the tubular member 6 is screwed to the distribution nozzle 13, and is sandwiched between the tip end side of the tubular member 6 and the large-diameter tubular portion 13A of the distribution nozzle 13, and the tubular member 6 is provided. The valve seat member is provided so as to close the front end side of the valve seat member 7, and the valve seat member 7 has a stepped tubular tubular portion 7A having a small diameter portion 7A1 and a large diameter portion 7A2 and an open end of the tubular portion 7A. And a flange portion 7B provided on the side, and a valve shaft insertion hole 7A3 is bored in the small diameter portion 7A1 in the axial direction. Further, the large diameter portion 7A2 of the cylindrical portion 7A becomes a valve chamber B having a hollow inside, and a plurality of flow holes 7A4, 7A4, ... Are tangentially directed from the outer peripheral surface side of the large diameter portion 7A2 toward the valve chamber B. Has been drilled.

The supercharged assist air ejected in a swirling flow state into the air chamber A from the respective vent holes 6C of the tubular member 6 is mixed with the injected fuel by swirling the swirl flow. In this state, the fuel is atomized in the valve chamber B by flowing tangentially into the valve chamber B through the respective flow holes 7A4. A valve seat 7C is formed on the inner edge of the large diameter portion 7A2 of the cylindrical portion 7A on the lower end side, and a valve body 8 described later is seated on the valve seat 7C.

Reference numeral 8 denotes a valve body provided on the valve seat member 7 of the cover 5, and the valve body 8 has a valve shaft 8A and a poppet type valve portion 8B provided on the tip side of the valve shaft 8A. , A disk-shaped spring bearing 8C provided on the base end side of the valve shaft 8A, and the valve body 8 is such that the valve shaft 8A can slide in the valve shaft insertion hole 7A3 of the valve seat member 7. It is inserted and attached. A valve spring 9 is provided between the spring receiver 8C of the valve body 8 and the large diameter portion 7A2 around the small diameter portion 7A1, and the valve spring 9 always closes the valve portion 8B. It is supposed to be urged. When the fuel and the supercharging assist air are supplied into the air chamber A and the valve chamber B, the valve body 8 is opened by the pressure at this time to generate a mixture of the fuel and the supercharging assist air. It is designed to eject from the valve seat 7C side. On the other hand, the valve body 8 is closed by the valve spring 9 when the fuel injection is stopped, and the combustion pressure and the like from the main combustion chamber 2A and the auxiliary combustion chamber C described later flow back into the air chamber A and the valve chamber B. Prevent.

Reference numeral 10 denotes a partition wall member provided between the injector 3 and the cylinder head 2 and provided in the mounting hole 2B of the cylinder head 2, and the partition wall member 10 is an injector 3 having a bottomed cylindrical shape. Holding cylinder 11 and a spark plug 1 which will be described later and extends obliquely upward from the side surface of the holding cylinder 11.
3, and a plug mounting portion 12 to which 3 is mounted. Here, the holding cylinder 11 has a tubular portion 11A and a bottom portion 11B, and the bottom portion 11B defines a sub combustion chamber C from the main combustion chamber 2A on the cylinder head 2 side inside the holding barrel 11. There is. Further, on the inner peripheral side of the tubular portion 11A, a stepped portion 11A1 is provided above the position where the plug mounting portion 12 branches.
However, the internal thread portion 11A2 is provided on the inner peripheral side of the upper end of the tubular portion 11A,
The cylindrical portion 11 is provided at an intermediate portion between the step portion 11A1 and the female screw portion 11A2.
A tubular air introducing portion 11A3 is formed to communicate the inside and outside of A and is connected to an air supply source (not shown).
A male screw portion 11A4 is formed on the outer peripheral side of the lower end of 1A. Further, a communication hole 11B1 that communicates with the main combustion chamber 2A is formed in the center of the bottom portion 11B, and the main combustion chamber 2A and the auxiliary combustion chamber C communicate with each other through the communication hole 11B1. The partition wall member 10 has a male screw portion 11 on the lower end side of the holding cylinder 11.
A4 is screwed into the mounting hole 2B of the cylinder head 2 and mounted on the engine body 1.

Reference numeral 13 denotes a distribution nozzle provided in the cylindrical portion 11A of the partition member 10, and a large diameter cylindrical portion 1 having a female screw 13A1 formed on the inner peripheral side at the base end side of the distribution nozzle 13.
3A is provided, and the stepped portion 1 is provided on the tip side of the large diameter cylindrical portion 13A.
3B and a conical portion 13C having a gradually decreasing diameter, and then a large-diameter cylindrical portion 1
A main nozzle portion 13D having the same axis center as 3A is formed. Here, the conical portion 13C is provided with a distribution hole 13E for communicating the inside of the large-diameter cylindrical portion 13A with the inside of the auxiliary combustion chamber C,
The distribution hole 13E has an opening area ratio set with the main nozzle portion 13D so that fuel and assist air can be distributed and injected into the auxiliary combustion chamber C and the main combustion chamber 2A at a predetermined ratio. Has been done.

That is, the sub combustion chamber C has a smaller volume than the main combustion chamber 2A, and even when a relatively small amount of fuel is injected from the distribution holes 13E of the distribution nozzle 13, the sub combustion chamber C will be described later. While producing a rich air-fuel mixture that can be reliably ignited by the sparks of the spark plug 15 that operates, a lean mixture suitable for performing lean combustion by mixing with intake air in the main combustion chamber 2A. In order to distribute the fuel so as to generate air, the distribution hole 13E partially discharges a part of the fuel ejected together with the supercharging assist air from the side of the air chamber A.
The main nozzle portion 13D guides the remaining fuel to the main combustion chamber 2A together with the supercharging assist air. Then, in the auxiliary combustion chamber C and the main combustion chamber 2A, an air-fuel mixture leaner than usual is produced on the average, and lean burn control is enabled. Further, the main nozzle portion 13D has a communication hole 11B1 of the holding cylinder 11 in the auxiliary combustion chamber C from the air chamber A side.
Is formed in a tubular shape by extending in the axial direction up to
An annular passage D is formed between 1B1 and the main nozzle portion 13D.

The distribution nozzle 13 has a large-diameter cylindrical portion 13
The threaded portion 6B of the tubular member 6 is screwed into the inside of A, and is attached inside the cover 5, and is inserted into the tubular portion 11A of the partition wall member 10 together with the cover 5, and a lid which will be described later from above the cover 5. By screwing the body 14 into the holding cylinder 11, the stepped portion 11A
It is sandwiched between 1 and the lid 14.

Reference numeral 14 denotes a cylindrical lid body having a screw 14A formed on the outer peripheral surface thereof, and the lid body 14 has a fitting hole 14 in the axial direction.
B is formed. Then, the fitting hole 14 of the lid 14
The injection nozzle 4B of the injector body 4 is fitted in B, and the injector body 4 is attached to the partition member 10. At this time, an annular air passage 11A5 communicating with the air introducing portion 11A3 is defined between the inner periphery of the cylindrical portion 11A of the partition wall member 10 and the outer periphery of the cover 5, and the air introducing portion 11A5 is formed.
The supercharging assist air supplied from A3 is introduced from the outside in the radial direction into the air chamber A from the vent hole 6C through the annular air passage 11A5 in a swirling flow state.

Reference numeral 15 indicates a spark plug, and the spark plug 1
Reference numeral 5 is attached to the plug attachment portion 12 of the partition wall member 10 so that the ignition portion 15A faces the sub combustion chamber C.

The assist air type fuel injection device according to this embodiment has the above-mentioned structure, and its operation will be described below.

First, when the fuel whose fuel pressure is adjusted is supplied to the connection port 4D of the injector body 4 from a fuel pipe (not shown) and a signal from the control unit is applied to the connector 4E of the injector body 4, the injector body 4 is injected. The needle valve 4C is opened, and the fuel is injected from the injection nozzle 4B into the air chamber A of the cover 5. Also,
At this time, pressurized air is supplied to the air introduction portion 11A3 of the partition wall member 10 from an air supply source (not shown), and this pressurized air becomes supercharging assist air, and each vent hole 6 is formed in the air chamber A.
It jets from C in a swirling state and swirls the fuel in the air chamber A.

When the valve body 8 is opened by the pressure of the fuel and assist air at this time, the fuel is swirling from the air chamber A into the valve chamber B through the flow holes 7A4 together with the supercharging assist air. At this time, the fuel is atomized and ejected from between the valve seat 7C of the valve seat member 7 and the valve body 8 into the conical portion 13C of the distribution nozzle 13.

Next, the distribution nozzle 13 distributes and supplies the fuel jetted from the injector 3 together with the supercharging assist air to the main combustion chamber 2A side and the sub combustion chamber C side, and the sub combustion chamber C is supplied.
A rich air-fuel mixture is generated therein so that ignition can be reliably performed by the ignition plug 15, and a lean air-fuel mixture M suitable for performing lean combustion is generated in the main combustion chamber 2A. And FIG.
As shown in FIG. 5, the ignition plug 15 ignites and burns the air-fuel mixture in the sub-combustion chamber C, and ejects the flame f generated in this way into the main combustion chamber 2A, so that the main combustion chamber 2A can be controlled even during lean burn control. The air-fuel mixture M is stably burned.

In particular, in this embodiment, the main nozzle portion 13D of the distribution nozzle 13 is formed in a tubular shape, and the inside of the auxiliary combustion chamber C is axially extended from the air chamber A side to the position of the communication hole 11B1 of the holding cylinder 11. Since the annular passage D is formed between the main nozzle portion 13D and the communication hole 11B1, the following effects are obtained.

That is, since the flame f ignited by the air-fuel mixture in the auxiliary combustion chamber C is blown into the main combustion chamber 2A from the annular passage D in the form of a hollow cylinder or hollow cone,
The flame f contacts the air-fuel mixture in the main combustion chamber 2A with a large area, and the air-fuel mixture can be efficiently burned to improve the combustion efficiency.

Further, since the main nozzle portion 13D of the distribution nozzle 13 is heated by burning the air-fuel mixture in the auxiliary combustion chamber C, the fuel injected from the inside of the main nozzle portion 13D into the main combustion chamber 2A is discharged. In addition to atomization of the fuel by the supercharging assist air, vaporization is promoted, and lean combustion can be reliably performed in the main combustion chamber 2A.

Thus, according to this embodiment, the atomization of the fuel is promoted by the supercharging assist air, and this fuel is distributed to the sub combustion chamber C and the main combustion chamber 2A, and the sub combustion chamber C is
Since the rich air-fuel mixture is ignited inside, the lean air-fuel mixture M in the main combustion chamber 2A can be surely burned by the flame f from the auxiliary combustion chamber C even during lean burn control. Therefore, it is possible to obtain a stable rotation output from the engine body 1 even during lean burn control, and to achieve various effects such as cleaning exhaust gas and improving fuel efficiency.

Next, FIG. 3 shows a second embodiment of the present invention. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted. The present embodiment is characterized in that the distribution hole of the distribution nozzle is formed so as to open in the auxiliary combustion chamber at a position separated from the ignition plug in the circumferential direction of the auxiliary combustion chamber.

In the figure, reference numeral 21 denotes a partition wall member used in this embodiment, and the partition wall member 21 is substantially the same as the partition wall member 10 described in the first embodiment and has a step portion 22A1 and a female screw portion 22A.
2, a bottomed cylindrical holding cylinder 22 having a cylindrical portion 22A having an air introducing portion 22A3, a male screw portion 22A4 and a communication hole 22B1 and a bottom portion 22B, and a plug mounting portion 23. A diffusion portion 22C is formed on the partition wall member 21 so as to face the plug mounting portion 23 in the radial direction and closer to the bottom portion 22B than the step portion 22A1 of the cylindrical portion 22A. Here, the diffusion portion 22C is the cylindrical portion 22A of the holding cylinder 22.
A distribution hole 2 of a distribution nozzle 24, which will be described later, is formed by forming a concave curve on the inner peripheral surface and extending in the circumferential direction of the cylindrical portion 22A.
The fuel and the supercharging assist air ejected from 4E are evenly dispersed in the auxiliary combustion chamber C.

Reference numeral 24 denotes a distribution nozzle provided in the cylindrical portion 22A of the partition wall member 21. The distribution nozzle 24 has a large diameter cylindrical portion 24A, which is similar to the distribution nozzle 13 described in the first embodiment. , The step portion 24B, the conical portion 24C, the main nozzle portion 24D, and the distribution hole 24E.
The distribution hole 24E is mounted in the holding cylinder 22 so that the distribution hole 24E faces the diffusion portion 22C of the partition member 21, and the distribution hole 24E is located at a position separated from the ignition plug 15 in the circumferential direction of the auxiliary combustion chamber C. It opens in the auxiliary combustion chamber C.

The assist air type fuel injection device according to the present embodiment has the above-mentioned structure and has substantially the same function and effect as those of the first embodiment, but particularly in this embodiment, the partition member 21 is held. A plug mounting portion 23 is provided in the cylinder 22.
A diffusion portion 22C is formed in the cylindrical portion 22A of the holding cylinder 22 so as to be opposed in the radial direction, and the fuel ejected together with the supercharging assist air from the distribution hole 24E of the distribution nozzle 24 is uniformly diffused in the auxiliary combustion chamber C. Since this is done, the following operational effects can be obtained.

That is, the fuel jetted together with the supercharging assist air from the distribution hole 24E of the distribution nozzle 24 toward the inside of the holding cylinder 22 is in contact with the diffusion part 22C and the diffusion part 2
The main nozzle portion 24 of the distribution nozzle 24 is guided by the curved surface of 2C.
Since it diffuses into the auxiliary combustion chamber C outside D, the ignition plug 15 is reliably ignited without causing a phenomenon such as fogging, without causing a partial fuel concentration difference in the air-fuel mixture in the auxiliary combustion chamber C. can do.

In the auxiliary combustion chamber C, the inner surface of the tubular portion 22A of the holding tube 22 and the outer surface of the distribution nozzle 24 are heated to a high temperature due to the combustion of the air-fuel mixture.
The fuel diffused in the auxiliary combustion chamber C along 2C is
The inner surface of A and the main nozzle portion 24D of the distribution nozzle 24 and the like are easily contacted with each other to be easily vaporized, and the ignitability of the spark plug 15 can be further improved.

Therefore, according to this embodiment, the distribution nozzle 2
Since the fuel injected into the auxiliary combustion chamber C from the distribution hole 24E of No. 4 can be quickly vaporized and diffused into the auxiliary combustion chamber C, the ignitability of the fuel in the auxiliary combustion chamber C can be improved. The flame f from the sub-combustion chamber C causes the main combustion chamber 2A
The combustion efficiency on the side can be further improved.

In each of the above embodiments, the partition member 10 (21) is provided so as to project from the cylinder head 2 to the outside, but the present invention is not limited to this, and for example, the partition member 10 (21). May be formed integrally with the cylinder head 2.

[0045]

As described in detail above, according to the present invention, the cylinder head of the engine body defines the main combustion chamber on the cylinder side and the auxiliary combustion chamber on the injector side between the injector and the injector. A partition wall member having a communication hole for communicating the auxiliary combustion chamber with the main combustion chamber is provided, and a part of the fuel ejected from the air chamber side together with the supercharging assist air is provided in the partition member. A distribution nozzle having a distribution nozzle for distributing the residual fuel to the main combustion chamber together with the supercharging assist air, and a fuel injected from the distribution hole of the distribution nozzle into the auxiliary combustion chamber. And a spark plug for burning the supercharged assist air in the auxiliary combustion chamber and ejecting a flame from the communication hole toward the main combustion chamber, and the main nozzle portion of the distribution nozzle communicates with the partition member from the air chamber side. Axis to hole position Since it is expanded in the direction of a tube to form a tube, the flame generated by igniting the air-fuel mixture in the auxiliary combustion chamber is made into a cylindrical or hollow conical shape between the main nozzle part of the distribution nozzle and the communication hole of the partition member. It can be ejected into the main combustion chamber, and this flame can be brought into contact with the air-fuel mixture in the main combustion chamber with a large contact area to greatly improve the fuel combustion efficiency.For example, even during lean burn control, stable output can be derived from the engine body. Therefore, it is possible to purify exhaust gas and improve fuel efficiency.

Further, the main nozzle portion of the distribution nozzle is heated by the combustion of the air-fuel mixture in the auxiliary combustion chamber.
The fuel ejected from the inside of the main nozzle portion is promoted to be vaporized, so that lean combustion can be surely performed in the main combustion chamber.

Further, if the distribution hole of the distribution nozzle is opened in the auxiliary combustion chamber at a position separated from the ignition plug in the circumferential direction of the auxiliary combustion chamber, injection is made from the distribution hole of the distribution nozzle toward the auxiliary combustion chamber. The vaporized fuel contacts the peripheral wall portion of the auxiliary combustion chamber and the outer surface of the main nozzle portion of the distribution nozzle that are in a high temperature state, promotes vaporization, and spreads evenly in the auxiliary combustion chamber. It is possible to reliably ignite with the spark plug without causing a specific concentration difference.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an assist air type fuel injection device according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in FIG.

FIG. 3 is an enlarged longitudinal sectional view showing a main part of an assist air type fuel injection device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Engine Body 2 Cylinder Head 2A Main Combustion Chamber 3 Injector 4B Injection Nozzle 10,21 Partition Member 11B1, 22B1 Communication Hole 13,24 Distribution Nozzle 13E, 24E Distribution Hole 13D, 24D Main Nozzle Part 15 Spark Plug A Air Chamber C Secondary Combustion Room f flame

Claims (2)

[Claims] 1. An engine body in which a combustion chamber is defined on the cylinder head side, and fuel is injected from an injection nozzle toward the combustion chamber of the engine body, and in-cylinder direct injection has an air chamber around the injection nozzle. In a cylinder head of the engine body, the combustion chamber is located between the injector and the main combustion chamber on the cylinder side and the auxiliary combustion chamber on the injector side. And a partition member having a communication hole for communicating the auxiliary combustion chamber with the main combustion chamber, the partition member being provided with one of the fuel injected from the air chamber side together with the supercharging assist air. Nozzle having a main nozzle portion for discharging the remaining fuel to the main combustion chamber together with the supercharging assist air, and a distribution hole of the distribution nozzle into the sub combustion chamber. An ignition plug is provided which burns the distributed and ejected fuel and the supercharging assist air in the auxiliary combustion chamber to eject the flame toward the main combustion chamber from the communication hole, and the main nozzle portion of the distribution nozzle is the air An assist air type fuel injection device, which is formed in a tubular shape by axially extending from a chamber side to a position of a communication hole of a partition member. 2. The assist air fuel injection system according to claim 1, wherein the distribution hole of the distribution nozzle is formed so as to open into the auxiliary combustion chamber at a position separated from the ignition plug in the circumferential direction of the auxiliary combustion chamber. apparatus.