KR20030088293A - Electronic control fuel injection device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically controlled fuel injection device, comprising: a plunger 21 driven by an electromagnetic force to feed and suck fuel, a cylinder 22 to 24 for housing the plunger 21 to define the feeding chamber C; The fuel supply passage 29a, the first valve body 30 allowing the fuel to flow into the pressure feeding chamber 30, the transfer passage 28a, and the cylinder 24 for returning the fuel in the pressure feeding chamber C to the transfer passage 28a. ) Is provided with a reflux passage 32a having a reflux port 24c on its side, a second valve body 31 disposed near the reflux port 24c, a spray nozzle 50, and the plunger 21 is a pressure stroke stroke. The reflux port 24c is opened in the initial region of the opening and the reflux port 24c is closed in the later region, whereby the air is removed only by the reciprocating motion of the plunger 21, so that stable fuel injection is performed. It is characterized by providing an electronically controlled fuel injection device suitable for the onboard engine.

Description

ELECTRONIC CONTROL FUEL INJECTION DEVICE

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronically driven electronically controlled fuel injection device for injecting fuel into an intake passage of an engine, and more particularly to an electronically controlled fuel injection device applied to an engine mounted on a motorcycle or the like.

In the engine of a relatively large displacement mounted on an automobile or the like, an electronically controlled fuel injection device for controlling fuel injection timing, injection quantity, etc. by an electronic circuit is adopted from the viewpoint of fuel efficiency improvement or driving performance improvement in response to emission gas regulation or the like. have.

The device is generally equipped with a fuel pump such as a mainstream type disposed in a fuel tank, a high pressure feed pipe for guiding the high pressure fuel fed from the fuel pump, a high pressure filter, and an electron for injecting the delivered fuel into the intake passage. The valve type injector, the return pipe which conveys the excess fuel from an injector to a fuel tank, etc. are provided.

On the other hand, a fuel injection device using a carburetor has been conventionally employed in an engine having a relatively small displacement, for example, about 50 cc to 250 cc of exhaust gas per vehicle mounted on a two-wheeled vehicle or an equivalent vehicle or other actuating device.

By the way, in the low displacement engine, even if the same system as the conventional electronically controlled fuel injection device is applied instead of the conventional carburetor, the driving performance required for two-wheeled vehicles and the like cannot be obtained without performing optimal fuel control.

In addition, since the conventional fuel pump of the mainstream type has a relatively large size, high power consumption, and a complicated structure, it is difficult to join the engine such as a two-wheeled vehicle. In addition, if a high-pressure supply pipe as in the prior art is adopted, it is not preferable from the viewpoint of safety in a two-wheeled vehicle or the like which has to consider conduction or the like.

In addition, when steam is generated in the fuel due to heat generation or passage resistance of the fuel pump, the injection amount of the fuel is not stabilized, so it is necessary to efficiently remove these generated steam.

The present invention has been made in view of the above point, and its object is to achieve low fuel consumption, low cost, small size, small space, and the like, and to achieve stable fuel injection while ensuring operational performance with a simple structure. An object of the present invention is to provide an electronically controlled fuel injection device suitable for a small displacement engine mounted on a motorcycle or the like.

1 is a configuration diagram showing a fuel supply system applying an electronically controlled fuel injection device according to the present invention; and

2 is a cross-sectional view showing an embodiment of the electronically controlled fuel injection device according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: fuel tank 2a: intake passage

3: supply pipe 4: low pressure filter

5: return pipe 10: electronically controlled fuel injection device

21: Plunger 22: Cylinder (Body)

23: Upper yoke (solid) 24: Lower yoke (solid)

24a: guide passage 24b: supply port

24c: outlet port 24d: outlet port

25: bobbin 26: coil

28: conveying pipe 28a: conveying passage

29: fuel supply pipe 29a: fuel supply passage

30: first valve body 30a: check valve

30b, 31b, 52a: spring 31: second valve body

31a: pressure valve 32: reflux pipe

32a: return passage 33: bypass passage

34: steam separation filter 50: fuel injection nozzle

51a: fuel passage 52: check valve

53: poppet valve 54: air supply pipe

54a: air supply passage

An electronically controlled fuel injection device of the present invention is an electronically controlled fuel injection device for injecting fuel into an intake passage of an engine, and includes a plunger driven by an electromagnetic force for feeding and inhaling fuel by reciprocating motion, and a plunger freely received. A cylinder defining a fuel delivery chamber, a fuel supply passage that can communicate with the pressure delivery chamber, a first valve body that allows the fuel in the fuel supply passage to flow into the delivery chamber, and a return to return a portion of the fuel to its original state. A reflux passage having a passageway and a reflux port on the side of the cylinder for refluxing the fuel in the feed chamber to the conveying passage, and an article disposed in the vicinity of the reflux port to allow the fuel having a predetermined pressure or more in the feed chamber to flow out into the reflux passage. 2 a valve body and the injection nozzle which inject | pours the fuel more than the predetermined | prescribed pressure which was arrange | positioned in the downstream of a pressure feed chamber, and was pumped, and a plunger is a pressure stroke It is characterized in that it is formed to open the reflux port in the initial region of and close the reflux port in the later region other than the initial region.

According to this configuration, the fuel is sucked into the pressure chamber from the fuel supply passage through the first valve body by the suction stroke of the plunger, and the steam mixed fuel pressurized at a predetermined pressure or higher in the initial region by the pressure stroke of the plunger to the reflux port. Flows from the injection nozzle via the second valve body in the vicinity to the reflux passage.

In this way, since the second valve agent allowing the outflow from the pressure feeding chamber is disposed near the reflux port, steam mixed in the fuel in the pressure feeding chamber is efficiently discharged into the reflux passage before injection and stable fuel injection is performed. Further, since the reflux port is formed on the side of the cylinder and is directly opened and closed by the plunger, opening and closing of the reflux port in the pressure feeding stroke is performed with high accuracy at a predetermined timing synchronized with the movement of the plunger.

In the above configuration, the supply port of the fuel supply passage may be formed on the side of the cylinder and the first valve body may be arranged in the vicinity of the supply port.

According to the said structure, since the pressure loss of the fuel which passed through the 1st valve body can be suppressed as much as possible, the steam which enters into a pressure transmission chamber with pressure loss can be suppressed. Moreover, since the 1st valve body and the 2nd valve body are arrange | positioned in the vicinity of the side surface of a cylinder body, components are integrated and the apparatus can be miniaturized.

In the above configuration, the reflux port may adopt a configuration that is arranged closer to the start side of the pressure feeding stroke than the supply port.

According to the above configuration, it is possible to quickly set the start time of the suction for the suction stroke of the plunger in the arrangement relationship between the reflux port and the supply port in the pressure chamber, and to set the timing of refluxing the fuel of the steam mixture in the initial region of the pressure stroke stroke. Can be set easily.

In the above configuration, a configuration in which the circumference of the cylinder has a bypass passage for guiding fuel from the fuel supply passage to the transfer passage can be adopted, and the reflux passage communicates with the bypass passage.

According to the above configuration, the heat passing through the electromagnetic drive of the flange can be cooled by the fuel passing through the bypass passage, and the generation of steam can be suppressed by the cooling action. In addition, the steam discharged from the reflux passage flows into the flow of fuel in the bypass passage and is smoothly discharged toward the conveyance passage without staying.

In the above configuration, the reflux port may adopt a configuration located in an upper region in the vertical direction with respect to the pressure feeding chamber.

According to this structure, the steam which generate | occur | produced in the pressure feed chamber can be discharged | emitted efficiently from the reflux port located in the upper area | region in a pressure feed chamber.

In the above configuration, the fuel passage is formed extending in a direction substantially perpendicular to the reciprocating direction of the plunger, the conveying passage is formed extending in the reciprocating direction of the plunger and pointing upward, and the bypass passage is annular to surround the cylinder. It is possible to adopt a configuration formed of.

According to this configuration, since the bypass passage is formed in the annular shape surrounding the cylinder, the cooling efficiency is increased and the generation of steam can be further suppressed. In addition, since the bypass passage is in communication with the conveyance passage facing upwards, the generated vapor can be reliably discharged toward the conveyance passage without remaining.

In the above configuration, a configuration in which a steam separation filter for separating steam mixed in the fuel is provided near the upstream side of the first valve body.

According to this configuration, when fuel flows into the pressure feeding chamber from the fuel supply passage via the first valve body, the steam in the fuel supply passage is separated by a steam separation filter, and only the fuel is actively introduced into the pressure feeding chamber. Inflow of is suppressed.

In the above configuration, the injection nozzle may adopt a configuration having an air supply passage for supplying air for atomizing the injected fuel.

According to this structure, since the steam supplied from the air supply passage agitates the fuel when the fuel is injected from the injection nozzle, atomization of the injection fuel is promoted.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described, referring an accompanying drawing.

1 and 2 show an embodiment of the electronically controlled fuel injection device according to the present invention, Fig. 1 is a schematic diagram of a fuel supply system to which the device is applied, and Fig. 2 is a sectional view of the device.

As shown in FIG. 1, the fuel supply system to which the apparatus is applied includes an electronically controlled fuel injection device 10 arranged at a fuel tank 1 of a two-wheeled vehicle, an intake passage 2a of an engine 2, and a fuel supply system. The supply pipe 3, the low pressure filter 4 arranged in the middle of the supply pipe 3, the return pipe 5 for conveying a part of the supplied fuel to the fuel tank 1, and controlling the driving of the apparatus 10. And an engine control unit (ECU) 6 including a drive circuit and the like.

As illustrated in FIG. 2, the electronically controlled fuel injection device 10 includes a plunger pump 20 driven by an electromagnetic force to transfer fuel, an injection nozzle 50 for injecting fuel pressurized above a predetermined pressure, or the like. 1, the conveying pipe 28 mentioned later is arrange | positioned upwards (almost perpendicularly upward or diagonally upward) in the state assembled with the engine 2 as shown in FIG.

As shown in FIG. 2, the plunger pump 20 is arranged outside the cylinder 22 and the cylinder 22 as a cylinder for slidably accommodating the flanger 21 to linearly reciprocate linearly, and the cylinder 22. The upper yoke 23 which forms a part, the lower yoke 24 which forms a part of a cylinder, and defines the pressure feed chamber C, and the lower yoke 24 are seated, and the plunger 21 is moved upward. Coil 26 wound around cylindrical bobbin 25 and bobbin 25 which are arranged at predetermined intervals with the outer circumferential surfaces of return spring 21a, upper yoke 23 and lower yoke 24 that press toward the stop position. , The conveying pipe 28 connected to the upper yoke 23 and the bobbin 25 to form the conveying passage 28a and the bobbin 25 and integrally formed to the lower yoke 24 to supply the fuel supply passage ( The fuel supply pipe 29 forming the 29a), the first valve body 30 allowing the inflow of fuel into the pressure feed chamber C, and the pressure feed chamber C And a second valve agent 31 for allowing reflux of the fuel to be discharged.

The plunger 21 is formed with the diameter reduction part and the diameter expansion part, and is hollowed so that the inside may open toward the conveyance path 28a side. The plunger 21 moves downward by the electromagnetic driving force generated when the coil 26 is energized to carry out the pressure feeding stroke of the fuel. On the other hand, when the energization to the coil 26 is cut off, the pressing force of the return spring 21a is applied. It is pushed upwards to carry out the fuel intake stroke.

As shown in FIG. 2, the lower yoke 24 is provided with a guide passage 24a for slidably guiding the distal end portion (lower region) of the plunger 21, and a fuel supply passage 29a is provided on the side of the guide passage 24a. ), A supply port 24b for supplying fuel to the pressure feed chamber C and a reflux port 24c for refluxing the fuel in the pressure feed chamber C are formed.

Near the outside of the supply port 24b, the first valve element 30, that is, the check valve 30a, and a check for allowing the fuel having a predetermined pressure or more in the fuel supply passage 29a to flow into the pressure feeding chamber C The spring 30b which pressurizes the valve 30a is arrange | positioned. Thus, since the 1st valve body 30 is arrange | positioned in the vicinity of the supply port 24b, the pressure loss of the fuel which reaches the pressure feed chamber C via the 1st valve body 30 can be suppressed as much as possible, Accompanied with this, steam generated in the pressure feeding chamber C can be suppressed.

A reflux pipe 32 that forms a reflux passage 32a is provided outside the reflux port 24c, and the reflux pipe 32 is located near the reflux port 24c to form a second valve body 31, namely The pressure provision valve 31a and the spring 31b which pressurize the pressure provision valve 31a for allowing the fuel more than predetermined pressure in the pressure feed chamber C to flow out to the return flow path 32a are arrange | positioned.

The said reflux port 24c and the 2nd valve body 31 discharge the fuel of the vapor mixture in the pressure feed chamber C toward the conveyance path 28a, and in this way, the 2nd valve in the vicinity of the reflux port 24c is carried out. By disposing the sieve 31, backflow of steam can be prevented and steam can be discharged efficiently.

In the guide passage 24a, the reflux port 24c is arranged in the region above the supply port 24b, i.e., when the plunger 21 descends from the upper side and starts the pressure feeding stroke, near the start side of the pressure feeding stroke. It is.

Therefore, since the supply port 24b is positioned relatively lower, when the flanger 21 moves from the lower side to the upper side and performs the suction stroke, the start timing of suction can be set quickly. In addition, since the reflux port 24c is located above, the timing for refluxing the fuel of the vapor mixture can be easily set in the initial region of the pressure feeding stroke.

In addition, the reflux port 24c is located in the upper region in the vertical direction in the pressure feeding chamber C. As shown in FIG. Therefore, the steam in the pressure feeding chamber C is efficiently discharged from the reflux port 24c toward the reflux passage 32a.

An annular bypass passage 33 is formed between the outer circumferential surfaces of the upper yoke 23 and the lower yoke 24 and the bobbin 25. The bypass passage 33 directs fuel from the fuel supply passage 29a to the transfer passage 28a. Therefore, the heat generated when the coil 26 is energized to drive the flanger 21 is cooled by the fuel passing through the bypass passage 33 and the heat generation of the entire apparatus is suppressed. This cooling action also suppresses the generation of steam.

In particular, the fuel supply passage 29a extends in the transverse direction substantially perpendicular to the reciprocating direction of the flanger 21, and the conveying passage 28a extends upward along the reciprocating direction of the flanger 21. The bypass passage 34 is formed in an annular passage (cylindrical passage) that extends upward.

Therefore, the mixed steam does not stay along the flow of fuel until the fuel supplied from the lower fuel supply passage 29a passes the bypass passage 33 and passes through the return passage 28a, and discharges upwards smoothly. do.

In addition, a steam separation filter 34 that actively passes only fuel is disposed on an upstream side of the first valve element 30. Therefore, the steam generated in the fuel supply passage 29a is actively led to the bypass passage 33 by the steam separation filter 34, so that the inflow into the pressure feed chamber C is suppressed.

In addition, the reflux passage 32a communicates with the lower region of the bypass passage 33. Therefore, the vapor mixed in the fuel discharged from the reflux passage 32a is drawn into the bypass passage 33 into the flow of fuel flowing from the lower side upwards to be actively discharged.

As shown in Fig. 2, the injection nozzle 50 has a check valve that allows only the outflow from the cylinder member 51 forming the fuel passage 51a and the discharge passage 24d formed at the lower end of the pressure chamber C. 52 and a spring 52a, a poppet valve 53 for opening the valve when the fuel is above a predetermined pressure, a spring 53a, and an air supply pipe 54 for forming the air supply passage 54a. Here, the air supply passage 54a supplies air that promotes atomization of the fuel.

Next, the operation of this apparatus will be described.

First, when the coil 26 is energized, an electromagnetic force is generated, and the plunger 21 in the upper stop position starts to move downward in response to the pressing force of the return spring 21a, and the fuel in the pressure chamber C The pressure feeding stroke is started while pressing.

In the initial region of the pressure feeding stroke, when the fuel to be pumped is equal to or higher than a predetermined pressure (pressure application), the pressure applying valve 31a is opened to open the reflux passage 32a, and the vapor mixing in the pressure chamber C Fuel is discharged toward the conveying passage 28a via the bypass passage 33.

Subsequently, when the plunger 21 moves further to enter the later region of the pressure feeding stroke, the side surface of the flanger 21 closes the reflux port 24c and further boosts the fuel in the pressure feeding chamber C.

Then, when the fuel in the pressure chamber C rises to the predetermined pressure, the check valve 52 is opened, the fuel having the predetermined pressure or more opens the poppet valve 53, and the fuel from which the steam is removed is intake passage. It is injected in 2a. At this time, the air supplied through the air supply passage 54a is mixed with the injected fuel to promote atomization and atomization of the fuel, and the fuel is injected in a uniform state without deflection.

On the other hand, the heat generated by the electromagnetic drive during the operation of the flanger 21 is cooled by the fuel flowing from the fuel supply passage 29a to the transfer passage 28a via the bypass passage 33. As a result, the heat generation of the apparatus is suppressed, and as a result, the generation of steam is also suppressed.

When energization to the coil 26 is cut off after fuel injection, the flanger 21 starts moving upwards by the pressing force of the return spring 21a. At this time, the check valve 30a is opened to start the suction stroke, and the fuel in the fuel supply passage 29a is sucked into the pressure feeding chamber C. As shown in FIG.

At this time, the vapor mixed in the fuel is actively separated by the vapor separation filter 34 and discharged toward the bypass passage 33.

In the injection of fuel, a control signal (pulse energizing signal to the coil 26) is generated to move in response to the cycle of the engine 2 from the engine control unit 6, so that the pressure stroke and the initial stroke of the pressure stroke are generated. A series of operations consisting of reflux (discharge) of steam, fuel feeding and discharging in the late region of the pressure feeding stroke, fuel injection and suction stroke by the injection nozzle 50 are repeated continuously.

In the said embodiment, although the annular bypass passage 33 was formed in the outer side of the cylinder, and the reflux passage 32a was made to communicate with the bypass passage 33, it is not limited to this and conveys the reflux passage 32a. You may employ | adopt the structure which communicates directly with the channel | path 28a.

As described above, according to the electronically controlled fuel injection device of the present invention, the components constituting the fuel supply system are simplified, miniaturized, and consumed by employing a self-pressurized fuel injection system that reciprocates by the electronic driving force to intake and pump fuel. Reduction of electric power or the like is achieved, and a fuel injection device that is optimal for a small displacement engine is provided. In particular, an initial stage of the pressure stroke stroke is provided on a side surface of a cylinder for slidably guiding the plunger so as to define the pressure chamber of the fuel, and providing a reflux port for refluxing the fuel of the steam mixture in the pressure chamber to the transfer passage and a second valve body in the vicinity thereof. Efficient and reliable discharge can be achieved while preventing backflow of the steam mixed fuel in the zone. Thereby, the injection of fuel is performed stably, and high precision fuel injection can be achieved by an engine mounted on a motorcycle or the like.

Claims (8)

An electronically controlled fuel injection device for injecting fuel into an intake passage of an engine, A flanger driven by an electromagnetic force for pumping and sucking fuel by a reciprocating motion, a cylinder for freely accommodating the flanger to define a pumping chamber of the fuel, a fuel supply passage communicating with the pumping chamber, and A first valve body allowing the fuel in the fuel supply passage to flow into the pressure feeding chamber, a conveying passage for returning a part of the fuel to its original state, and a side surface of the cylinder for refluxing the fuel in the pressure feeding chamber into the conveying passage. A reflux passage having a reflux port, a second valve body disposed in the vicinity of the reflux port to allow the fuel having a predetermined pressure or more in the pressure chamber to flow out of the reflux passage, and a downstream side of the pressure chamber to be fed An injection nozzle for injecting fuel above a predetermined pressure, wherein the plunger opens the reflux port in an initial region of the pressure feeding stroke; In the late region of the group other than the initial region the electronic control fuel injection device, characterized in that it is formed so as to close the old reflux. The method of claim 1, An supply port of the fuel supply passage is formed on the side of the cylinder, and the first valve body is disposed in the vicinity of the supply port. The method according to claim 1 or 2, And the reflux port is arranged closer to the start side of the pressure feeding stroke than the supply port. The method according to any one of claims 1 to 3, And a bypass passage around the cylinder to lead fuel from the fuel supply passage to the transfer passage, And the reflux passage communicates with the bypass passage. The method according to any one of claims 1 to 4, And the reflux port is located in an upper region in the vertical direction with respect to the pressure feeding chamber. The method according to any one of claims 1 to 5, The fuel passage is formed extending in the direction orthogonal to the reciprocating direction of the plunger, The conveying passage is formed to extend in the reciprocating direction of the plunger and to face upward; And the bypass passage is formed in an annular shape so as to surround the cylinder. The method according to any one of claims 1 to 6, An electronically controlled fuel injection device, characterized in that a vapor separation filter for separating steam mixed in the fuel is provided near the upstream side of the first valve element. The method according to any one of claims 1 to 7, And the injection nozzle has an air supply passage for supplying air for atomizing the injected fuel.