JP2003172225A - Electronically controlled fuel injection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronically controlled fuel injection system capable of making a cylinder wall thin by restraining sliding resistance of a plunger pump arranged in a fuel injection system from increasing. <P>SOLUTION: In the electronically controlled fuel injection system, a pair of yokes (13 and 15) are fitted to a cylinder 8 with an gap in its axial direction and a gap ring 38 is fitted to the cylinder and located between both the yokes for limiting the gap of the yokes. Concave and convex fitting parts 38a and 38b for limiting the positions of the gap ring and both the yokes to be on the same axis are formed at a opposed part to the gap ring and both the yokes. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled fuel injection device, and more particularly to an electronically controlled fuel injection device used in an internal combustion engine mounted on a vehicle such as a motorcycle.

[0002]

2. Description of the Related Art Conventionally, for example, in an internal combustion engine mounted on a vehicle such as a two-wheeled vehicle, fuel is sent to a fuel injection nozzle while being pressurized by a fuel injection pump, and the fuel injection nozzle atomizes it into an intake passage. A so-called electronically controlled fuel injection device for supplying is used.

In order to send the fuel to the fuel injection device, the fuel injection device and the fuel tank in which the fuel is stored are connected by a fuel supply pipe.

The applicant of the present invention has proposed, as the above-mentioned electronically controlled fuel injection device, one having a structure shown in FIG. The electronically controlled fuel injection device indicated by reference numeral 1 in this figure includes a body 6, a plunger pump P mounted inside the body 6 to suck and feed the fuel F, and an injection mounted to the body 6 to inject fuel. The plunger pump P includes a nozzle 7, a cylinder 8, a plunger 10 slidably mounted in the cylinder 8 to form a pressurizing chamber 9, and a solenoid coil 11 for exciting the plunger 10. The body 6 is provided with a suction contact pipe 12 constituting the suction portion 1a at the lower portion thereof, and the return portion 1b at the upper portion thereof.
The return contact pipe 13 constituting the above is provided, and further, between the cylinder 8 and the solenoid coil 11, a part of the fuel branched in the suction unit 1a is returned.
An annular flow path 14 is provided for guiding toward b.

A return contact pipe 13 is fitted on the cylinder 8 so as to cover the outer periphery of the upper portion of the cylinder 8 to form an upper yoke for forming a magnetic path. Further, an outer cylinder 15 is fitted on the lower portion of the cylinder 8. A lower yoke that is fitted to form a magnetic path is configured, and further, the outer cylinder 1
5 and the return contact pipe 13 between the intermediate pipe 1
6 is interposed.

[0006]

By the way, in such a conventional fuel injection device, the interval between the return contact pipe 13 forming the upper yoke and the outer cylinder 15 forming the lower yoke is set to the intermediate pipe 16. And the return contact pipes 13,
The outer cylinder 15 and the intermediate pipe 16 cover the outer peripheral portion of the cylinder 8 so that the plunger 10 mounted in the cylinder 8 can slide.

However, since the intermediate pipe 16 is only brought into contact with the return contact pipe 13 and the outer cylinder 15 in the axial direction, the intermediate pipe 16 is relatively moved in the radial direction at the time of assembly due to processing precision of parts. It may move or fall. Then, in such a case, there is a problem that a load is applied to the cylinder 8 and the cylinder 8 is deformed to increase a sliding resistance of the plunger 10 that can be slid in the cylinder 8 and a required drive current increases. To be

And, in order to solve such a problem,
It is possible to increase the strength of the cylinder 8 by increasing the wall thickness of the cylinder 8. However, in such a case, there is a problem that the distance between the plunger 10 and the yoke is widened to prevent passage of magnetic flux, resulting in an increase in the required drive current.

The present invention has been made in view of the above-mentioned conventional problems, and suppresses an increase in sliding resistance of a plunger pump arranged in a fuel injection device and enables a thin cylinder. An object is to provide an electronically controlled fuel injection device.

[0010]

According to a first aspect of the present invention, there is provided an electronically controlled fuel injection device for injecting fuel into an intake passage of an internal combustion engine in order to achieve the above object. And a body and a plunger pump that is mounted in the body and sends the fuel under suction pressure.
An injection nozzle that is mounted on the body and injects the fuel, and the plunger pump includes a cylinder, a plunger slidably mounted in the cylinder, and a space in the cylinder in the axial direction. And a pair of yokes fitted in the cylinder, and fitted in the cylinder,
It is composed of a gap ring interposed between the both yokes to regulate the distance between them, and a solenoid coil for exciting the plunger, and positionally regulates the gap ring and the two yokes coaxially with each other. It is characterized in that a concavo-convex fitting portion is formed. In the electronically controlled fuel injection device according to claim 2 of the present invention, the concavo-convex fitting part according to claim 1 is an annular convex part formed at one end of the yoke and the gap ring, It is characterized in that it is constituted by an annular concave portion formed at the other end and into which the annular convex portion is fitted.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a fuel supply system to which the electronically controlled fuel injection device 1 of the present embodiment is applied. This fuel supply system is an electronic control for injecting the fuel F into the intake passage I of the internal combustion engine by sucking the fuel F from the fuel tank 2 and pressurizing the fuel F below the fuel tank 2 in which the fuel F is stored. A fuel injection device 1 is provided, and a suction portion 1a provided at a lower portion of the electronically controlled fuel injection device 1 and a fuel tank 2 are connected by a feed pipe 3 for supplying a fuel F, and the electronically controlled fuel injection is performed. The returning portion 1b provided at the upper portion of the device 1 and the fuel tank 2 are connected by a return pipe 4 for returning the surplus fuel discharged from the electronically controlled fuel injection device 1 to the fuel tank 2, and further in the middle of the feed pipe 3. Is provided with the low-pressure filter 5.

As shown in FIG. 2, the electronically controlled fuel injection device 1 includes a body 6, a plunger pump P mounted in the body 6 for sucking and feeding the fuel F, and a body 6 mounted in the body 6. A plunger pump P is provided with an injection nozzle 7 for injecting, and a plunger pump P is slidably mounted in the cylinder 8 to form a pressurizing chamber 9.
0 and a solenoid coil 11 that excites the plunger 10. The body 6 has a suction portion 1 at the bottom thereof.
a suction contact pipe 12 constituting a is provided,
A return contact pipe 13 forming a return portion 1b is provided in the upper portion, and a part of the fuel branched in the suction portion 1a is directed to the return portion 1b between the cylinder 8 and the solenoid coil 11. An annular flow path 14 is provided for guiding. And the return contact pipe 13
However, as in the conventional case, the upper yoke covers the upper portion of the cylinder 8.

An outer cylinder 15 that covers the lower portion of the cylinder 8 and forms a lower yoke is fitted in the lower portion of the cylinder 8, and a gap ring is provided between the outer cylinder 15 and the return contact pipe 13. Three
8 is interposed.

Then, a concavo-convex fitting portion 38a is provided at a portion of the gap ring 38 opposed to the return contact pipe 13 and the outer cylinder 15 so as to coaxially position them.
・ 38b is formed. Then, in the present embodiment, the concave-convex fitting portions 38a and 38b have the gap ring 3
8 is formed by an annular convex portion 39 formed at the end and an annular concave portion 40 formed in the return contact pipe 13 or the outer cylinder 15 and into which the annular convex portion 39 is fitted.

An annular core 17 is fitted so as to cover the return contact pipe 13, the gap ring 38, and the outer cylinder 15, and the solenoid coil 11 is wound around the core 17, and Core 1
An annular flow path 14 is formed between the inner peripheral surface of 7 and the return contact pipe 13, the intermediate pipe 16, and the outer peripheral surface of the outer cylinder 15.

The lower portion of the outer cylinder 15 is projected from below the body 6, and a measuring orifice 18 communicating with the pressurizing chamber 9 is mounted inside the projecting end.

A discharge passage 10a is formed at the center of the plunger 10 for guiding the excess fuel to the return portion. A preload is applied to the fuel F in the discharge passage 10a at the initial stage of the pressurizing stroke of the plunger 10. A preload valve 19 is provided.

Inside the outer cylinder 15, a sub-cylinder 20 is mounted above the metering orifice 18 at a distance from the lower end of the plunger 10, and the outer peripheral surface of the sub-cylinder 20 and the outer cylinder 15 are attached. A pressurizing chamber 9 is formed between the inner peripheral surface and the inner peripheral surface of the cylinder 8.

At the upper end of the sub cylinder 20,
When the preload operation by the plunger 10 is completed, the spill valve 21 is brought into contact with the plunger 10 to shield the discharge passage 10a to start the fuel pressurizing operation.
Further, an outlet check valve 22 that is opened at the time when the pressure of the fuel F in the pressurizing chamber 9 reaches a predetermined pressure is provided at the lower end of the sub-cylinder 20.

Further, at the lower end portion of the outer cylinder 15 where the suction contact pipe 12 is mounted, a suction passage 15a for connecting the suction contact pipe 12 and the pressurizing chamber 9 is formed, This suction path 15
In the middle of a, the fuel F is supplied only during the suction stroke of the plunger 10.
An inlet check valve 23 is provided as a check valve that allows the inflow into the pressurizing chamber 9.

A branch passage 24 is formed in the outer cylinder 15 so as to communicate with the annular flow passage 14 and the suction passage 15a to communicate with the inlet check valve 23 upstream of the suction passage 15a. 12
A part of the fuel F sucked in through is constantly guided to the return passage 14.

On the other hand, the injection nozzle 7 has a nozzle body 25 fitted on the outer periphery of the lower end portion of the outer cylinder 15, and a tubular guide member 2 arranged in the nozzle body 25.
6, a tubular holding member 27 reciprocally mounted inside the guide member 26, and a fuel injection formed on the guide member 26 reciprocally mounted inside the holding member 27. It is constituted by a poppet valve 29 that opens and closes the passage 28.

Then, reference numerals 30 and 31 in FIG.
Is a neutral spring for holding the plunger 10 in the neutral position, and reference numerals 32, 33, 34, and 35 respectively denote a preload valve 19, a spill valve 21, an outlet check valve 22, and a poppet valve 29. A return spring for urging the closed position is shown, and a reference numeral 36 is a return spring for urging the inlet check valve 23 to the closed position.

Further, in FIG. 2, reference numeral 37 supplies air to the injection nozzle 7 by the negative pressure in the intake passage I when the injection nozzle 7 is opened to atomize the fuel injected from the injection nozzle 7. Assisted air orifice.

Next, the operation of the electronically controlled fuel injection device 1 according to this embodiment having the above structure will be described. The plunger pump P is synchronized with the cycle of the internal combustion engine.
Is activated, the plunger 10 is reciprocated,
The fuel F in the fuel tank 2 is sucked into the pressurizing chamber 9 through the feed pipe 3 and then pressurized, so that the injection nozzle 7
Is injected into the intake passage I in a mist state via.

That is, the suction of the fuel F is performed by the plunger 1
When 0 is returned to the neutral position, the pressurizing chamber 9 is made to have a negative pressure, whereby the inlet check valve 23 is opened and the fuel F is sucked into the pressurizing chamber 9 from the suction passage 15a. It

As a result, when the plunger 10 is excited by the solenoid coil 11, the plunger 10 is excited.
However, the fuel F in the pressurizing chamber 9 starts to be pressurized by being lowered against the elasticity of the neutral spring 31. Then, in such an initial stage of the pressurizing stroke, the inlet check valve 23 is closed and the pressurizing chamber 9 is closed.
The fuel F in the inside is pressurized, but when the pressure of the fuel F is increased to a predetermined pressure, a part of the fuel in the pressurizing chamber 9 is partially discharged by the action of the preload valve 19. 10
By being discharged to a, the fuel F in the initial stage of the above-described pressurization stroke is held at a predetermined pressure.

When the lowering of the plunger 10 is continued, the lower end surface of the plunger 10 is closed by the spill valve 21, so that the fuel F in the pressurizing chamber 9 is further pressurized and the pressure thereof reaches a predetermined pressure. At the time of rising, the outlet check valve 22 is opened, the fuel F in the pressurizing chamber 9 is sent to the injection nozzle 7 through the metering orifice 18, and thereafter, the poppet valve 29 is opened, so that the fuel is discharged. F is injected into the intake passage I via the fuel injection passage 28. Then, during such fuel injection, the assist air is supplied from the assist air orifice 37, so that the atomization of the injected fuel F is accelerated and supplied to the intake passage I as described above.

During such fuel injection, the return contact pipe 13 and the outer cylinder 15 and the gap ring 38 are connected by the concave and convex fitting portions 38a and 38b, so that their relative positions can be changed. , Is surely regulated not only in the axial direction but also in the radial direction. As a result, the return contact pipe 13, the outer cylinder 15, and the gap ring 38 are integrated with each other, and a mounting hole for the cylinder 8 is linearly formed inside them, and the mounting hole is formed. Be sure to keep it straight.

Therefore, the return contact pipe 1
3, outer cylinder 15, and gap ring 3
The outer periphery of the cylinder 8 mounted in the cylinder 8 is covered with a continuous cylindrical inner surface without displacement, and the cylinder 8
It is surely prevented from applying a load that deforms. This suppresses an increase in the sliding resistance of the plunger 10 mounted in the cylinder 8 and reduces the drive current.

The shapes, sizes, etc. of the constituent members shown in the above embodiment are merely examples, and can be variously changed based on design requirements and the like.

[0032]

As described above, according to the electronically controlled fuel injection device according to the present invention, the pair of yokes and the gap ring are connected to each other by the concave and convex fitting by the concave and convex fitting portions so as to connect them to each other. The positional relationship can be reliably regulated not only in the axial direction but also in the radial direction. As a result, these two yokes and the gap ring are integrated to form a mounting hole for the cylinder in a straight line inside them, and the mounting hole can be surely held in a straight line. The outer periphery of the cylinder can be covered with a continuous inner surface of the cylinder without displacement, and it is possible to reliably prevent application of a load that deforms the cylinder. As a result, the sliding resistance of the plunger mounted in the cylinder can be reduced and the drive current can be reduced. Further, since the thrust of the plunger is improved more than the weight reduction and the cost reduction due to the thinned cylinder, current consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a fuel supply system to which an electronically controlled fuel injection device according to an embodiment of the present invention is applied.

FIG. 2 is an enlarged vertical cross-sectional view of a main part showing an embodiment of the present invention.

FIG. 3 is an enlarged vertical sectional view of a main part showing a conventional example.

[Explanation of symbols]

1 Electronically controlled fuel injection device 1a suction part 1b Return section 2 fuel tank 3 feed pipes 4 Return pipe 5 Low pressure filter 6 body 7 injection nozzle 8 cylinders 9 Pressurization chamber 10 Plunger 10a discharge path 10b suction path 11 solenoid coil 12 Suction contact pipe 13 Return contact pipe (upper yoke) 14 ring flow path 15 Outer cylinder (lower yoke) 15a suction path 16 Intermediate pipe 17 core 18 metering orifice 19 Preload valve 20 sub cylinders 21 spill valve 22 Outlet check valve 23 Inlet check valve 24 forks 25 nozzle body 26 Guide member 27 Holding member 28 Fuel injection passage 29 poppet valve 30 Neutral spring 31 Neutral Spring 32 Return spring 33 Return spring 34 Return spring 35 Return spring 36 Return spring 37 Assist air orifice 38 Gap Ring 38a Concavo-convex fitting part 38b Concavo-convex fitting part 39 annular protrusion 40 annular recess F fuel I Intake passage P Plunger pump

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadashi Nijuki             2480 Kuno, Odawara-shi, Kanagawa Co., Ltd.             Mikuni Odawara Office (72) Inventor Hiroshi Mizui             2480 Kuno, Odawara-shi, Kanagawa Co., Ltd.             Mikuni Odawara Office F term (reference) 3G066 AA01 AB02 AD10 BA56 BA61                       CA09 CC06U CC14 CE22                 3H071 AA07 BB01 CC33 DD84

Claims (2)

[Claims] 1. An electronically controlled fuel injection device for injecting fuel into an intake passage of an internal combustion engine, a body, a plunger pump mounted in the body for sucking and feeding the fuel, and mounted on the body. And a plunger pump slidably mounted in the cylinder and the cylinder, the plunger pump being fitted into the cylinder at a distance in the axial direction thereof. A pair of yokes, a gap ring fitted over the cylinder and interposed between the yokes to regulate the distance between the yokes, and a solenoid coil for exciting the plunger. An electronically controlled fuel injection device, characterized in that a concavo-convex fitting portion for restricting the positions of these yokes coaxially with each other is formed in a portion facing each other. 2. The concavo-convex fitting portion is an annular convex portion formed at one end portion of the yoke or the gap ring, and an annular convex portion formed at the other end portion to which the annular convex portion is fitted. The electronically controlled fuel injection device according to claim 1, wherein the electronically controlled fuel injection device is configured by a recess.