JP2780527B2 - Fuel injection system for multi-cylinder internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for a multi-cylinder internal combustion engine in which a fuel injection valve and an air control valve for injecting assist air near the injection port are combined.

[0002]

2. Description of the Related Art Japanese Patent Application No. 3-14 filed earlier by the present applicant.
The specification and drawings of the third application disclose an air-assisted fuel for an internal combustion engine in which a fuel injection valve and an air control valve for injecting assist air near the injection port in synchronization with the fuel injection are combined. An injection device is described. The air-assisted fuel injection device mixes fuel with an appropriate amount of pressurized air by using an air control valve near the injection port in order to atomize the fuel injected into the intake port of the internal combustion engine. However, according to the above-mentioned prior art, the need to reduce harmful substances in exhaust gas, etc., in order to improve the combustion state by promoting atomization or vaporization of the spray, the internal combustion from the injection port of the fuel injection valve A so-called long nozzle having a relatively long mixture passage reaching the vicinity of the intake valve of the engine is attached to the fuel injection valve, and a heater is provided around the mixture passage to heat the mixture of fuel spray and air. Things.

[0003] In the fuel injection device disclosed in the above prior art, no detailed structure is disclosed for the air control valve which has no direct relation to the gist thereof, and the positional relationship with the fuel injection valve is not particularly mentioned. However, when this fuel injection device is attached to the intake port of each cylinder of a multi-cylinder internal combustion engine, the problem is how to determine the positional relationship between the fuel injection valve and the air control valve. come.

In this case, the most conceivable arrangement in the prior art is as shown in FIG. That is, a long nozzle 14 having a fuel injection valve 12 of a fuel injection device 10 is attached to an intake port 4 formed in a cylinder head 2 of each cylinder on the upstream side near an intake valve (not shown). Is attached to the nozzle body 15 of the long nozzle 14 in a virtual plane parallel to the fuel injection valve 12 and perpendicular to a common virtual plane formed by the fuel injection valve 12 of each cylinder. This maximizes the space 8 formed between the cylinder head 2 and the branch pipe 6 to each cylinder of the intake manifold, and minimizes the length of the fuel injection device 10 in the crankshaft direction. This is because it is likely that the length of the internal combustion engine itself in the crankshaft direction can be reduced.

[0005]

When the fuel injection valve 12 and the air control valve 16 of the fuel injection device 10 are mounted on the cylinder head 2 of the internal combustion engine in a positional relationship as shown in FIG. This will make the best use of the space 8 formed between the intake manifold and the branch pipe 6 to each cylinder, but instead, as can be seen from FIG.
The degree of freedom in mounting the fuel injection device 10 with respect to the cylinder head 2 depends on the long nozzle 1
In order to avoid collision between the nozzle body 15 of FIG. 4 and the cylinder head 2 or the branch pipe 6, there is a problem that the nozzle body 15 must be extremely small.

Accordingly, the present invention provides a sufficient degree of freedom in the angle and position of attaching the fuel injection device 10 to the intake port 4 of the internal combustion engine while preventing the axial length of the fuel injection device 10, and therefore the internal combustion engine body, from increasing. Keep it large
It is an object of the present invention to provide a novel means for selecting an optimal mounting position.

[0007]

According to the present invention, as a first means for solving the above-mentioned problem, a fuel constituting a part of each of a group of fuel injection devices corresponding to a plurality of cylinder groups is provided. Each central axis of the injection valve and each central axis of the air control valve constituting another part of each of the group of fuel injection devices so as to supply assist air to the vicinity of the injection port of the fuel injection valve are provided. Wherein the fuel injection valves and the air control valves of the group of fuel injection devices are arranged and attached to the internal combustion engine body such that substantially all of them are included in the same virtual plane. In addition to providing the fuel injection device in a multi-cylinder internal combustion engine, in addition to the first means, both ends of the group of fuel injection devices are the same type of fuel injection valve or air control valve as the second means. Is characterized by A fuel injection device in a multi-cylinder internal combustion engine that.

[0008]

In the first solution, all the central axes of the fuel injection valves and the air control valves belonging to a group of fuel injection devices corresponding to the plurality of cylinder groups of the multi-cylinder internal combustion engine are substantially equal to each other. Are arranged so as to be in the same virtual plane, so that the space occupied by the group of fuel injection devices becomes a relatively thin flat plate, and the intake manifold connected to the cylinder head of the internal combustion engine and the intake port Since there will be sufficient margin in the conflict with the branch pipe etc.
A large degree of freedom can be obtained for selecting the inclination angle of the virtual plane and the position of the fuel injection valve in the direction of the central axis. In the second solution, in addition to the first, since both ends of a group of fuel injection devices are the same type of fuel injection valve or air control valve, the fuel is provided only by the distance between the fuel injection valve and the air control valve. As a result, the length of the injection device in the crankshaft direction is reduced, and the size of the internal combustion engine body can be reduced while maintaining the performance.

[0009]

FIG. 1 is a partial sectional view showing a detailed structure of one fuel injection device attached to an intake port 4 of one cylinder in an embodiment of a fuel injection device for an internal combustion engine according to the present invention. It is. Needless to say, since the present invention is applied to a multi-cylinder internal combustion engine, the fuel injection device is used except when one fuel injection device 10 as illustrated in FIG. 3 is shared among a plurality of cylinders. The fuel injection devices 10 are provided one by one for each cylinder. In the present invention, the plurality of fuel injection devices 10 and the fuel injection valve 12 and the air control valve 16 which are the components thereof are in any positional relationship with each other. Since the arrangement is a problem, the specific detailed structure of the fuel injection device 10 is not limited to that shown in FIG.

As shown in FIG. 3, one fuel injection device 10 according to the embodiment mainly includes three parts: a fuel injection valve 12, a long nozzle 14, and an air control valve 16. Reference numeral 18 denotes a common delivery pipe shared by the plurality of fuel injection devices 10, and in the illustrated embodiment, a fuel passage 20 for sending pressurized fuel to the fuel injection valve 12, and an air control valve 16 and an air passage (not shown) for sending the pressurized air,
It is formed in parallel in an integral delivery pipe 18.

A tubular fuel receiving portion 22 formed at a base end portion of the fuel injection valve 12 has an opening 24 provided through a wall of the delivery pipe 18 so as to communicate with a fuel passage 20 of the delivery pipe 18. It is inserted to receive fuel pressurized from the fuel passage 20. Further, a tubular air receiving portion 2 formed at the upper end of the air control valve 16 is provided.
Similarly, 6 is inserted into an opening 28 provided in the wall of the delivery pipe 18, communicates with an air passage (not shown) in the delivery pipe 18, and receives pressurized air into the air control valve 16.

In order to seal the space between the receiving portions 22 and 26 and the openings 24 and 28 of the delivery pipe 18 into which the receiving portions 22 and 26 are inserted, an O-ring 30 and a groove formed in the receiving portions 22 and 26 are provided. 32 are fitted respectively. Further, the fuel receiving portion 22 and the air receiving portion 26 are formed with flange portions 34 and 36, respectively, which are stoppers when the receiving portions 22 and 26 are inserted into the respective openings 24 and 28 of the delivery pipe 18. Becomes

The long nozzle 14, and thus the fuel injection device 1
0 is a posture as shown in FIG.
(The angle of the central axis XX and the position in the direction of the central axis XX) are attached to the intake port 4 in the cylinder head 2 of each cylinder of the internal combustion engine, and are shared by the plurality of fuel injection devices 10. 18 is also indirectly attached to the internal combustion engine body by means not shown, so that a plurality of sets of fuel injection valves 12 and air control valves 1 are provided.
Each of the pairs 6 is sandwiched between the main body 15 of the heater-equipped nozzle 14 and the delivery pipe 18 to be easily and reliably supported.

For this purpose, the fuel injection valve 1 is provided on the nozzle body 15 of the long nozzle 14 made of a tough, heat-insulating and heat-resistant material such as epoxy resin.
An opening 42 into which the second tip 40 is inserted is provided, as well as an opening 46 for receiving the tip 44 of the air control valve 16. An O-ring 48 for sealing between the distal end portion 40 and the opening 42 is fitted in the groove of the distal end portion 40 of the fuel injection valve 12, and the O-ring 48 is formed between the distal end portion 44 of the air control valve 16 and the opening 46. Between them, for example, a seal ring 50 made of rubber is inserted.

When actually assembling the fuel injection device 10 and attaching it to the internal combustion engine, first, the long nozzles 14 are attached to the intake ports 4 of the cylinder head 2 of the internal combustion engine by the number of cylinders, and then the fuel of each group is set. The injection pipe 12 and the air control valve 16 are inserted into the opening 42 and the opening 46, respectively, and the delivery pipe 18 is attached to the engine such that they are pressed by the delivery pipe 18 common to each group.

As shown in FIG. 3, a heater 52 is integrated with the nozzle body 15 of the long nozzle 14 by being partially embedded. The heater 52 of the illustrated embodiment is integrally formed of a metal having high thermal conductivity such as aluminum up to the tip of the nozzle, and has a heating element 52a such as a so-called PTC heater embedded therein. PTC (Positi
ve Temperature Coefficient) A heater is a ceramic electric heater with a positive temperature characteristic in which the electrical resistance value rises sharply as the temperature rises. Then, the current decreases and the temperature is maintained at a substantially constant level.
Suitable for use as a.

A small-diameter injection port (not shown) is opened at the upper end of a fuel passage 54 that penetrates the center of the front end portion 40 of the fuel injection valve 12, and is also reciprocated vertically by a solenoid (not shown) and a spring. When the needle opens the injection port, pressurized fuel supplied from the fuel passage 20 of the delivery pipe 18 through the fuel receiving portion 22 is sprayed into the fuel passage 54 in a spray form. . In the fuel passage 54, several air injection ports 5
6 are open, and these air nozzles 56
To the air control valve 16. Air control valve 16
As with the fuel injection valve 12, the delivery pipe 1 is operated by a valve opened and closed by a solenoid (not shown).
The pressurized air supplied from an air passage (not shown) 8 is sent from the communication passage 58 to the air injection port 56 in accordance with the fuel injection, and into the fuel spray injected from the fuel injection valve 12 into the fuel passage 54. Spray and mix well.

The fuel-air mixture is supplied to the heater 5 following the fuel passage 54.
2 and, in the illustrated embodiment, a long nozzle 14 integrated therewith.
The fuel is uniformly mixed while flowing through the mixture passage 62 formed at the front end portion 60 of the nozzle, the atomization of the fuel spray is promoted, and the heat generated by the heating element 52 a embedded in the heater 52 is generated by the wall surface of the mixture passage 62. , At least a part of the spray is vaporized and ejected from the front end opening 64 into the intake port of the internal combustion engine. When the engine is started or when the engine is operated in a low temperature state, the heating element 52a is energized to
By heating the fuel spray, the fuel spray is atomized and not only mixes well with the air, but also prevents the fuel spray from adhering to the wall surface of the mixture passage 62 in the form of droplets. By homogenizing and maintaining an appropriate air-fuel ratio, the combustion state is improved, the harmful substances in the exhaust are reduced, and the responsiveness and the output / fuel efficiency characteristics are also improved. In addition. FIG.
Denotes a heat insulator made of, for example, heat-resistant rubber.

Corresponding to the features of the present invention, the fuel injection device in the illustrated embodiment has a structural feature as shown in FIGS. 1 and 2 as compared with that shown in FIG. The first feature is that, as shown in FIGS. 1A and 2, all the fuel injection valves 12 of all the fuel injection devices 10 are in the same virtual plane including their central axes XX. Not only are they arranged and mounted so that they are all at the same angle to each cylinder of the internal combustion engine, but also, the center axis YY of the air control valve 16 also belongs to the same virtual plane, That is, all the air control valves 16 are arranged.

As a result, all the fuel injection valves 12 are included in the flat region having a relatively small thickness, so that the fuel injection valve 12 is formed in the space 8 formed by the cylinder head 2 and the branch pipe 6 of the intake port. With the margin around the fuel injection device 10,
A virtual plane X-X- with respect to the cylinder head 2 at the time of design
The Y-Y angle can be freely selected over a fairly wide range, as shown as θ in FIG. 2, and the installation depth of the fuel injection valve 12 and the air control valve 16 in the central axis direction is also increased. As shown by d in FIG. 2, the range of choice is increased. For both of these reasons, the degree of freedom in designing the mounting position of the fuel injection device 10 is greatly increased, and the fuel injection device 10 is mounted so as to maintain an optimal posture at an optimal position, thereby enabling its performance to be fully exhibited.

The second feature is, in addition to the first feature, FIG.
(B), one internal combustion engine or V
In the case of a type engine or the like, in one bank, the fuel injection valves 12 and the air control valves 16 of the plurality of fuel injection devices 10 are
Not only are all the fuel injection devices 10 arranged in a common virtual plane X-X-Y-Y, but both ends of a plurality of fuel injection devices 10 are of the same type. That is, in the embodiment of FIG. 1B, the components arranged at both ends are arranged so as to be the fuel injection valves 12, and in the embodiment not shown, both ends are arranged so as to be the air control valves 16. Is done.

As described above, the same virtual plane XXYYY is used.
By arranging all the central axes of the group of fuel injection valves 12 and the air control valves 16 within the group, the embodiment of FIG. 1B is different from the embodiment of FIG. By comparison, the length of the delivery pipe 18 in the crankshaft direction can be shortened by an amount corresponding to the interval P between the fuel injection valve 12 and the air control valve 16, and as a result, the fuel injection device 10
Not only can be reduced in size, but also the length of the internal combustion engine body in the crankshaft direction can be shortened. This makes it possible to downsize the engine while maintaining the performance of the engine.

[0023]

According to the present invention, the degree of freedom in mounting the fuel injection device to the internal combustion engine body is greatly increased,
It is possible to mount the fuel injection device so as to be at the optimum angle and position, not only to exert its performance sufficiently, but also to make both ends of a group of fuel injection devices the same type of fuel injection valve or air control valve. In this case, the lengths of the fuel injection device, the delivery pipe, and the main body of the internal combustion engine in the direction of the crankshaft can be reduced, so that the size of the internal combustion engine can be reduced as a whole.

[Brief description of the drawings]

FIG. 1 is a front view showing the overall configuration of two embodiments (a) and (b) of the present invention in contrast.

FIG. 2 is a side sectional view showing a common sectional shape with respect to FIG. 1 (a) or (b).

FIG. 3 is an enlarged longitudinal front view showing one fuel injection device in the embodiment.

FIG. 4 is a side sectional view showing an arrangement example of a fuel injection device for comparison with the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 ... Cylinder head 4 ... Intake port 6 ... Branch pipe of intake manifold 8 ... Space 10 ... Fuel injection device 12 ... Fuel injection valve 16 ... Air control valve 18 ... Delivery pipe 54 ... Fuel passage 56 ... Air injection port 62 ... Mixture passage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-234567 (JP, A) JP-A-1-176754 (JP, U) JP-A-59-123661 (JP, U) JP-A-3-123 104172 (JP, U) JP-A 1-179175 (JP, U) JP-A 3-6056 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02M 69/04 F02M 69 / 00 F02M 51/02 F02M 61/08

Claims (2)

(57) [Claims] An assist air is supplied to each central axis of a fuel injection valve constituting a part of a group of fuel injection devices corresponding to a plurality of cylinder groups, and to the vicinity of an injection port of the fuel injection valve. The group of fuel injection devices such that the respective central axes of the air control valves constituting the other part of each of the group of fuel injection devices are substantially all included in the same virtual plane. A fuel injection device for a multi-cylinder internal combustion engine, wherein the fuel injection valve and the air control valve of the device are arranged and attached to an internal combustion engine body. 2. A fuel injection device for a multi-cylinder internal combustion engine according to claim 1, wherein both ends of said group of fuel injection devices are fuel injection valves or air control valves of the same kind.