JPH08319918A - Fuel injection device of internal combustion engine - Google Patents

Abstract

PURPOSE: To provide a fuel injection device of an internal combustion engine which can effectively cool a solenoid coil without increasing the moving resistance of a solenoid valve. CONSTITUTION: A fuel injection device of an internal combustion engine which receives fuel and high pressure air and injects the fuel with the high pressure air into an engine combustion room is provided with a passageway 51 which the mixture of fuel and high pressure air passes before it is injected into the engine combustion room. The passageway 51 is formed in a position neighboring on a coil casing 73 covering a solenoid coil 60 of a solenoid valve 58.

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 an internal combustion engine that injects fuel into an engine combustion chamber together with high pressure air.

[0002]

2. Description of the Related Art In a fuel injection device for injecting fuel into a combustion chamber by using high pressure air of this type, a solenoid valve is usually provided in a nozzle facing the combustion chamber.
In order to prevent the solenoid coil for operating the solenoid valve from burning due to heat generation, it is necessary to cool this coil. Here, in the prior art, for example, there is one in which air is allowed to pass through the inside of the coil (see Japanese Patent Publication No. 63-500322), but there is a problem that the cooling capacity is low. Further, there is one in which the solenoid coil is sealed with a diaphragm seal, and the sealed portion is filled with fuel to cool the coil (see Japanese Patent Laid-Open No. 63-248965). It is necessary to attach the diaphragm seal, and this diaphragm seal becomes a resistance against the movement of the solenoid valve, and there is a fear that smooth valve operation cannot be obtained.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to effectively use a solenoid coil without increasing the movement resistance of the solenoid valve. An object of the present invention is to provide a fuel injection device for an internal combustion engine that can be cooled.

[0004]

In order to achieve such an object, the present invention provides a fuel for an internal combustion engine which receives fuel and high pressure air and injects the fuel together with the high pressure air into an engine combustion chamber through a solenoid valve. The injector includes a passage through which a mixture of fuel and high-pressure air passes before being injected into the engine combustion chamber, the passage being formed at a position adjacent to a coil casing that covers a solenoid coil of a solenoid valve. is there.

[0005]

According to the present invention, the fuel mixed with the high-pressure air is vaporized by absorbing the heat of the solenoid coil when passing through the passage formed at the position adjacent to the coil casing. The solenoid coil is effectively cooled. That is, the heat of the solenoid coil is transferred to the fuel through the coil casing, so that the fuel mixed with the high pressure air is vaporized.

[0006]

The present invention will be described below based on the embodiments shown in the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to an internal combustion engine (hereinafter referred to as an engine) for a two-cycle outboard motor, for example. Reference numeral 10 denotes the entire engine, and as is well known, this two-cycle engine 1
0 opens and closes by the piston 16 reciprocating the exhaust port 13, the exhaust port 13, and the exhaust port 14 formed in the cylinder block 12. The piston 16 is connected to a crankshaft 18 via a connecting rod 17. An intake passage 24 having a reed valve 22 faces a crank chamber 20 that houses the crankshaft 18, and a throttle valve 25 is arranged in the intake passage 24. The cylinder head 26 is provided with an ignition plug 28 and a fuel injection device 30 according to the present invention, both of which face the fuel chamber 32.

The high-pressure air from the air conditioner 34 driven by the crankshaft 18 is introduced into the fuel injection device 30 through a pipe 35, and the high-pressure air introduced into the fuel injection device 30 is supplied by a regulator 36. The pressure-controlled excess surplus high-pressure air is returned to the intake passage 24 via the pipe line 37. The conduit 37 may be open to the atmosphere.

Further, the fuel from the fuel tank 40 is pulsated by the fuel pump 41 and then introduced into the fuel injection device 30 through the conduit 43. The fuel pressure of the fuel is regulated by the regulator 44. The residual heat fuel is returned to the fuel tank 40.

Next, FIG. 2 shows the structure of the first embodiment of the fuel injection device 30 in detail. First, reference numeral 50 is a fuel injector as a fuel supplier.
0 receives a part of the fuel introduced from the fuel tank 40 through the conduit 43, and injects a predetermined flow rate of fuel from the nozzle 55 through the solenoid valve 54 operated by the solenoid coil 52 thereof.

A solenoid valve 58 for opening and closing the injection nozzle 56 facing the engine fuel chamber is arranged substantially coaxially with the solenoid valve 54 of the fuel injector 50.
8 is operated by a solenoid coil 60. 72 is a bobbin of the solenoid coil 60, and 73 is a coil casing for covering the outer circumference of the solenoid coil 60. A hole 51 penetrating in the axial direction is formed in the coil casing 73, and a solenoid valve 58, a retainer 62, and a coil spring 66 are arranged in the hole 51. As is well known, the retainer 62 is attached to the upper portion of the solenoid valve 58, and the coil spring 66 is interposed between the retainer 62 and the main body casing 64 of the fuel injection device.
The solenoid valve 58 is urged upward through the retainer 62 to close the opening of the injection nozzle 56.

The fuel injector 50 is provided on the top surface of the retainer 62.
Nozzle 55 of the fuel injector 50 is introduced, and the fuel from the fuel injector 50 flows from the nozzle 55 to the fuel passage 68 formed in the retainer 62.
And is supplied to the hole 51. Further, the high-pressure air is introduced into the space between the fuel injector 50 and the retainer 52 from the above-mentioned air compressor 34 through the pipe 35, and passes through the air passage 70 formed in the retainer 62,
It is supplied to the holes 51. The fuel and the high-pressure air are mixed in the hole 51 and supplied into the injection nozzle 56. That is, the hole 51 serves as a passage for the mixture of fuel and high pressure air.

A fuel passage 74 is formed between the outer circumference of the coil casing 73 and the inner circumference of the main body casing 64 of the fuel injection device. The fuel passage 74 is sealed from the outside by a pair of O-rings 76 on both sides thereof. The fuel passage 74 communicates with a communication passage 77 formed in the main body casing 64. In the communication passage 77, the fuel supplied from the fuel tank 40 to the fuel injector 50 via the communication passage 43 of the pipeline. Is partly branched and supplied. Reference numeral 78 is a plug of the communication passage 77.

Reference numeral 80 is a ring nut attached to an internal thread formed on the inner peripheral wall of the main body casing 64, and 82 is a lock nut also attached to the inner wall of the main body casing 64 to lock the ring nut 80. Therefore, the solenoid coil 60 is positioned by the both sides through the coil casing 73.

Reference numeral 83 is an O-ring interposed between the fuel injector 50 and the main body casing 64.

According to the above construction, the hole (passage) 51 through which the mixture of fuel and high-pressure air passes is formed at a position adjacent to the coil casing that covers the solenoid coil 60 of the solenoid valve 58 facing the engine fuel chamber. The solenoid coil 60 is effectively cooled by the fuel and high pressure air.

The solenoid coil 60 is effectively cooled by the fuel supplied to the fuel passage 74. Here, the fuel passage 74 is formed by being sealed between the coil casing 73 and the main body casing 64 by the O-ring 76, so that no moving resistance is given to the movable portion of the valve. Further, the solenoid coil 60 can be completely sealed, and it is possible to prevent the fuel from leaking from the lead-out portion of the coil.

Further, the solenoid valve 5 of the fuel injector 50
4 and the solenoid coil 52 and the solenoid valve 58 for high pressure air and the solenoid coil 60 are arranged substantially coaxially.
Is not required to be extremely long, and valve response is improved. Further, as shown in FIG. 2, since the entire apparatus is made thin and compact, the problem of the installation space of this apparatus can be solved.

Further, according to the first embodiment, since the solenoid coil 60 is fixed by the ring nut 80 and the lock nut 82 via the coil casing 73, the movement amount of the solenoid valve 58 itself can be easily adjusted. . That is, in the past, for example, Japanese Patent Publication No. 63-50
As described in the publication No. 0322, the solenoid coil was fixed to the coil casing with a lock nut or the like via the return spring of the valve, but with this configuration, the valve movement amount can be adjusted to the coil fixing position. Therefore, if the adjustment of the movement amount is incomplete even when the coil is pressed down, it is necessary to disassemble the coil and valve assembly again and adjust the movement amount again. There was a problem. On the other hand, according to the above-described embodiment, the solenoid coil 60 is fixed to the body casing 64 by the ring nut 80 independently of the coil spring 66 serving as the return spring and the retainer 62, so that the amount of movement of the valve is reduced. Adjustment work becomes extremely easy.

Further, since the solenoid coil 60 is integrally mounted in the main body casing 64 through the coil casing 73, the casing for the coil does not leak fuel from the mating surface of the main body casing as in the conventional case.

[0021]

As described above, according to the present invention, since the passage through which the mixture of fuel and high-pressure air passes is formed at the position adjacent to the coil casing that covers the solenoid coil of the solenoid valve, the solenoid coil is Thus, it is possible to provide a fuel injection device for an internal combustion engine that can be effectively cooled by high pressure air.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a fuel injection device for an internal combustion engine according to the present invention.

FIG. 2 is a cross-sectional view showing in detail an embodiment of the fuel injection device of the present invention.

[Explanation of symbols]

 32 combustion chamber 51 hole (passage) 58 solenoid valve 60 solenoid coil 73 coil casing

Claims (1)

[Claims] 1. In a fuel injection device for an internal combustion engine, which receives fuel and high-pressure air and injects the fuel together with the high-pressure air into an engine combustion chamber via a solenoid valve, a mixture of fuel and high-pressure air is injected into the engine combustion chamber. With a passage that passes in front,
The fuel injection device for an internal combustion engine, wherein the passage is formed at a position adjacent to a coil casing that covers a solenoid coil of a solenoid valve.