JPS6079154A - Electronic control fuel injection device - Google Patents

Abstract

PURPOSE:To improve the cooling performance of a solenoid coil by forming an orifice on a fuel passage around the case of an electromagnetic fuel injection valve stored in the fitting hole of a throttle body and allowing fuel to flow from the upstream side through the periphery of a bobbin wound with the solenoid coil. CONSTITUTION:An electromagnetic fuel injection valve 6 sucks a core 33 and a needle 29 against a spring 36 via the magnetic force of a stator 22 generated when a pulse current is applied to a solenoid coil 38 from an electronic control unit 14, opens an injection nozzle 31, and injects the fuel in a needle chamber 26 into an intake passage. In this case, a fuel passage 7 is formed between the fitting hole 5 of a throttle body 3 and the case 20 of the fuel injection valve 6 stored in the hole 5, and an orifice 25 consisting of continuous lugs 24 formed around the case 20 is provided on the fuel passage 7. The fuel upstream the orifice 25 is allowed to flow through a communicating port 27, the needle chamber 26, gaps 41, 42 around a bobbin 39 wound with the solenoid coil 38, and an outflow port 47, and the solenoid coil 38 is cooled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel injection device for an engine using an electromagnetic fuel injection valve.

[Prior art to the invention]

An electronically controlled fuel injection system for an engine applies a pulse current to the electromagnetic coil of an electromagnetic fuel injection valve from an electronic controller such as a computer, and the magnetic force generated in the electromagnetic coil causes the needle to rev. It is known that fuel is injected from this nozzle hole by opening it. When the pulse current application start timing and application time are controlled by an electronic controller, the fuel injection start timing and fuel injection time are controlled.

In such a fuel injection valve, when a pulsed flow is applied to the electromagnetic coil from an electronic controller, the coil generates heat due to the resistance of the coil. The amount of heat generated varies depending on the pulse time and pulse period, but under severe conditions the electromagnetic coil may burn out, rendering the fuel injection valve inoperable.

In order to prevent burnout of the electromagnetic coil, various systems have been developed to cool the electromagnetic coil with fuel.
Japanese Patent No. 136864 is known, but in the conventional type, a sufficient cooling effect could not be obtained because the amount of fuel for cooling the coil was insufficient or the fuel remained.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an electronically controlled fuel injection device that efficiently cools an electromagnetic coil with fuel and prevents the electromagnetic coil from being overheated and burnt out.

[Structure of the invention]

The present invention forms a fuel passage between the inner peripheral surface of a mounting hole formed in a throttle body and the outer peripheral surface of a case of an electromagnetic fuel injector accommodated in this mounting hole, and -〇 this fuel passage is throttled. A fuel supply pump is connected to the upstream side of this throttle, and a pressure regulating valve is connected to the downstream side of this throttle, and the fuel passage is connected through a communication port formed in the body of the electromagnetic fuel injection valve. The upstream side of the aperture is communicated with a needle chamber, and the needle in this needle chamber is lifted by the magnetic force of an electromagnetic coil housed in the case to inject fuel from the nozzle hole, and the electromagnetic coil is wound within the case. A gap is provided around the bobbin, and this gap communicates with the needle chamber and an outlet opened in the side wall of the case, and this outlet opens into the fuel passage downstream of the throttle. Features.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure 1 shows the overall structure of an electronically controlled fuel injection device, and shows 1
is the engine. A throttle body 3 is connected to an intake pipe 2 connected to an engine 1, and a throttle valve 4 is attached to the throttle body 3. A mounting hole 5 is formed in the throttle body 3.
An electromagnetic fuel injection valve 6 is housed in the . A fuel passage 7, which will be described later, is formed between the mounting hole 5 and the electromagnetic fuel injection valve 6, and a fuel supply passage 8 and a fuel outflow passage 9 are connected to this fuel passage 7. The fuel supply path 8 is connected to a fuel supply pump 10 , which pumps up fuel from a fuel tank 11 and pumps the fuel through a filter 12 to the fuel path 7 through the fuel supply path 8 . Further, the fuel outflow path 9 is connected to a pressure regulating valve 13, and this pressure regulating valve 13 communicates with the fuel tank 11. The pressure of the fuel between the pump 10 and the pressure regulating valve 13 is regulated by the pressure regulating valve 13.

FIG. 2 shows an enlarged view of the electromagnetic fuel injection valve 6 and its surroundings in FIG. 1. The electromagnetic fuel injection valve 6 is in case 2.
0, a case 20 including a body 21 and a stator 22;
The body 21 and stator 22 are integrally supported by caulking the lower end and the upper end, respectively. The fuel injection valve 6 inserted into the mounting hole 5 of the slotted body 3 has O-rings 23a between the case 20 and the mounting hole 5, and between the body 21 and the mounting hole 5, respectively.

23b, and between these O-rings 23a and 23b, there is a connection between the outer peripheral surface of the case 20 and the mounting hole 5.
The above-mentioned fuel passage 7 is formed between the inner peripheral surfaces of the fuel passage 7.

A projection 24 continuous in the circumferential direction is provided on the outer peripheral surface of the case 20.
A throttle 25 is formed between the outer peripheral surface of the protrusion 24 and the inner peripheral surface of the mounting hole 5. For this reason, the fuel passage 7 is divided by the throttle 25 in the vertical direction shown in the drawing. Fuel supply path 8 connected to fuel supply pump 10
is opened at the lower part of the fuel passage 7 defined by the throttle 25, and the fuel outflow passage 9 communicating with the pressure regulating valve 13 is opened at the upper part of the fuel passage 7 defined by the throttle 25. . Therefore, fuel passage 7
The lower side in the figure than the throttle 25 is the upstream side of the fuel flow,
The upper side of the throttle 25 in the drawing is the downstream side of the fuel flow. Due to the existence of the throttle 25, the fuel pressure is lower on the downstream side than on the upstream side.

A needle chamber 26 is formed in the body 21 located upstream of the fuel passage 7, and this needle chamber 26 communicates with the upstream side of the fuel passage 7 via communication ports 27... Note that a filter 28 is attached to each of these communication ports 27.

A needle 29 is slidably inserted into the needle chamber 26. The needle 29 has a chamfered portion 3 chamfered on four sides.
0a, 30b are formed, and these chamfered portions 30a, 30
b is in sliding contact with the inner surface of the needle chamber 26, however, a gap is formed between the inner surface of the needle chamber 26 and the inner surface of the needle chamber 26. When this needle 29 is lifted, it opens the injection hole 31 at the lower end of the needle chamber 26 and injects the fuel in the needle chamber 26 into the throttle body 3. The needle 29 is guided into the case 20 by freely passing through a horseshoe-shaped spacer 32 sandwiched between the case 20 and the body 21, and the core 33 is guided through a two-sided chamfered portion 30G formed at the upper end of the needle 29. is fixed. A gap is formed between the inner surface of the core 33 and the chamfered portion 30C. The core 33 is axially opposed to the stator 22. A rod 34 is fixed to the stator 22 liquid-tightly by an O-ring 35 and by caulking the stator 22. A spring 36 is provided between the rod 34 and the needle 29. Therefore, the needle 29 receives the pressing force of the spring 36 and closes the nozzle hole 31.

Note that the lift of the needle 29 is restricted by the flange 37 coming into contact with the spacer 32.

An electromagnetic coil 38 is interposed between the case 20 and the stator 22. The electromagnetic coil 38 is wound around a bobbin 39. The bobbin 39 is fluid-tightly attached to the case 2o and the stator 22 by O-rings 40a and 40b, respectively, and gaps 41 and 42 are secured between the case 20 and the stator 22 and the bobbin 39. Furthermore, radial protrusions 43 are formed on the lower surface of the bobbin 39 as shown in the figure, and these protrusions 43 form a passage 44 between the lower surface of the bobbin 39 and the case 20, allowing the gaps 41 and 42 to communicate with each other. is formed. One of the spaces 41 communicates with the needle chamber 26 via a first passage 45 consisting of between the stator 22 and the core 33, between the core 33 and the needle 29, and between the needle 29 and the spacer 320. Further, this gap 41 is a second gap formed between the core 33 and the case 20 and between the needle 29 and the spacer 32.
It communicates with the needle chamber 26 via a passage 46 .

An outlet 47 is formed in the side wall of the case 20, and the outlet 47 is opened downstream of the end 25 of the fuel passage 7. This outlet 47 is connected to the gap 4 mentioned above.
It is connected to 2. Note that a filter 48 is provided at the outlet 47.
is press-fitted.

The electromagnetic coil 38 is connected to an electronic controller 14 such as a combination controller, and the electronic controller 14 applies a pulse current to the electromagnetic coil 38 according to the operating condition of the engine 1.

Note that 15 is a resin molded electrical connector. Furthermore, the fuel injection valve 6 is fixed to the throttle body 3 via a rubber bush 16 and a cover 17 .

9- The operation of the embodiment having such a configuration will be explained.

Fuel sent from the fuel supply pump 10 through the fuel supply passage 8 flows into the fuel passage 7 upstream of the throttle 25. This fuel is restricted to 11 by the throttle 25 and
It flows downstream from 5.

Therefore, the fuel pressure in the fuel passage 7 on the downstream side of the throttle 25 is kept low.

Fuel on the upstream side of the fuel passage 7 flows into the needle chamber 26 through the communication port 27. When a pulse current is applied to the electromagnetic coil 38 from the electronic control 814, a magnetic force is generated in the stator 22, and this magnetic force causes the core 33 and the needle 29
is attracted against the pressing force of the spring 36, and the needle 29 is lifted, opening the injection hole 31 and injecting the fuel in the needle chamber 26 into the throttle body 3.

The fuel injection timing and injection amount are controlled t11 by the electronic controller 14, and are determined by the pulse period T and pulse time T1, as shown in FIG.

The fuel in the needle chamber 26 flows from the chamfered portion 30b of the needle 29 through the first passage 45 and the second passage 46 into the gap 41 formed in the inner circumference of the bobbin 39. The fuel r1 in this gap 41 flows through a passage 44 formed in the lower surface of the bobbin 39 to a gap 42 formed in the outer circumference of the bobbin 39. And the fuel in this gap 42 is case 2
The fuel flows to the downstream side of the throttle 25 of the fuel passage 7 through an outlet 47 opened in the side wall of the fuel passage 7 .

Therefore, since the area around the bobbin 39 comes into contact with the fuel, even if the electromagnetic coil 38 generates heat, it is cooled by the fuel. Moreover, since the fuel around the bobbin 39 is constantly flowing, heat exchange is good, and therefore the cooling efficiency of the coil 38 is extremely good.

The flow of fuel around the bobbin 39 is maintained by the fact that the fuel pressure in the needle chamber 26 is higher than that on the downstream side of the fuel passage 7, and in order to generate such a pressure gradient, there is a By forming the throttle 25, the flow of fuel from the needle chamber 26 toward the downstream side of the fuel passage 7 through the gaps 41, 42 can be ensured.

In order to form the throttle 24 in the fuel passage 7, the protrusion 24 is formed on the case 20 of the electromagnetic fuel injection valve 6 in the above embodiment, but the present invention is not limited to this. A protrusion may be formed on the inner peripheral surface of the attachment hole 4. However, if the protrusion 24 is formed on the case 20 of the electromagnetic fuel injection valve 6, there is no need for any special modification to the throttle body 3, and it is easy to implement because only the electromagnetic fuel injection valve 6 needs to be modified. .

〔Effect of the invention〕

As detailed above, according to the present invention, a restriction is formed in the fuel passage formed between the mounting hole of the throttle body and the case of the electromagnetic fuel II feed valve to generate a pressure gradient in the fuel passage. , from the high pressure part on the upstream side of the fuel passage, to the needle chamber,
A gap is formed around the bobbin around which the electromagnetic coil is wound, and a fuel passage is formed that extends to the downstream low-pressure part of the fuel passage, so the electromagnetic coil and bobbin are cooled by the fuel, and this fuel is constantly flowing. The above cooling efficiency becomes extremely high. Therefore, the electromagnetic coil is prevented from being overheated, and the inoperability of the electromagnetic fuel injection valve due to burnout of the electromagnetic coil is prevented.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a diagram showing the overall structure of an electronic fuel injection device, and FIG. 2 is a sectional view showing an enlarged main part thereof. 3...Throttle body, 5...Mounting hole, 6...
Electromagnetic fuel injection valve, 7... Fuel passage, 10... Fuel supply pump, 13... Pressure regulating valve, 20... Case, 2
DESCRIPTION OF SYMBOLS 1...Body, 22...Stator, 24...Protrusion, 25...Aperture, 26...Needle chamber, 27...
Communication port, 29... Needle, 31... Nozzle hole, 33.
... Core, 38 ... Electromagnetic coil, 43 ... Protrusion, 4
4...Aisle, 45...First aisle, 46...Second
passage, 47...outlet. Applicant's representative Patent attorney Takehiko Suzue 13- Applicant, Yota Jidosha Co., Ltd. 1, Indication of the case Japanese Patent Application No. 187439/1982 2, Name of the invention Electronically controlled fuel injection device 3, Person making the amendment Relationship to the case Patent applicant (426) Nippon Denso Co., Ltd. (and 1 other person) 4. Agent 6 Drawing subject to amendment 7. Contents of amendment Among the applicants listed in the drawing attached to the application, "Nippon Hatsujo Co., Ltd." is attached as an attachment. The name has been corrected to ``Nippondenso Co., Ltd.'' as if the dividend had not been paid.

Claims (2)

[Claims] (1) The inner peripheral surface of the mounting hole formed in the throttle body,
A fuel passage is formed between the outer peripheral surface of the case of the electromagnetic fuel injection valve housed in the mounting hole, a throttle is formed in the fuel passage, and a fuel supply pump is connected to the upstream side of the throttle, A pressure regulating valve is connected downstream of this throttle,
Through the communication port formed in the body of the electromagnetic fuel injection valve, the upstream side of the throttle of the fuel passage is communicated with the needle chamber, and the needle in the needle chamber is lifted by the magnetic force of the electromagnetic coil housed in the case to fuel the fuel. is injected from the nozzle hole, and a gap is provided in the case around the bobbin around which the electromagnetic coil is wound, and this gap is communicated with the needle chamber and an outlet opened in the side wall of the case. An electronically controlled fuel injection device characterized in that the outlet is opened to a fuel passage downstream of the throttle. (2) Claim (1) characterized in that the throttle is formed between a protrusion formed on the outer peripheral surface of the case of the electromagnetic fuel injection valve and the inner peripheral surface of the mounting hole. The electronically controlled fuel injection device described in .