WO2001034963A1

WO2001034963A1 - Electronically controlled fuel injection device

Info

Publication number: WO2001034963A1
Application number: PCT/JP2000/003177
Authority: WO
Inventors: Naoki Kobayashi; Toshio Sugii; Junichiro Takahashi; Ryoji Ehara; Shogo Hashimoto
Original assignee: Mikuni Corporation
Priority date: 1999-11-11
Filing date: 2000-05-18
Publication date: 2001-05-17
Also published as: JP2001140733A

Abstract

An electronically controlled fuel injection device, comprising a solenoid valve driven injector (30) injecting fuel into the intake passage of an engine, a plunger pump (50) force-feeding fuel contained in a fuel tank (40) toward the injector, a fuel pressure regulator (80 or 90) of inlet control or outlet control performing fuel circulation to/from the fuel tank while regulating the pressure of fuel led from the plunger pump (50) to the injector (30), and a control unit (103) transmitting control signals to at least the injector based on the engine operating information, whereby the electronically controlled fuel injection engine low in power consumption and cost and small in size can be provided for an engine of small displacement mounted on a motorcycle.

Description

Description Electronically controlled fuel injection device Technical field

The present invention relates to an electronically controlled fuel injection device applied to supply fuel to an internal combustion engine (hereinafter, simply referred to as an engine), and particularly to an electronically controlled fuel injection device applied to a small displacement engine. . Background art

Conventionally, four-cycle gasoline engines installed in automobiles, etc., especially gasoline engines with medium or large displacements of 3 to 8 cylinders with a total displacement of about 600 to 400 cc From the viewpoint of improving fuel efficiency or operability in response to emission regulations and the like, electronically controlled fuel injection devices that control the fuel injection timing, injection amount, and the like using an electronic circuit are used.

As shown in FIG. 9, for example, as shown in FIG. 9, the electronic control fuel injection device is a solenoid valve driven injector which is attached to the intake passage in the intake manifold 2 of the engine 1 so as to be inclined downstream. According to 3, there is known a port injection type that injects fuel toward an intake port of an engine 1. In this port-injection type electronically controlled fuel injection device, as shown in the figure, the fuel (gasoline) in the fuel tank 4 is supplied by an in-tank type fuel pump 5 housed inside, for example, a circumferential flow type fuel pump. It is pressurized by a pump and sent out, and on the way through a high-pressure filter 6, supplied from a high pressure-resistant fuel feed pipe 7 and a delivery pipe (not shown) to the π-cutter 3. On the other hand, the fuel guided by the fuel feed pipe 7 is also sent to the fuel pressure regulator 8, and excess fuel other than the fuel injected from the injector 3 is returned to the fuel tank 4 again through the fuel return pipe 9. It is. As a result, the pressure (fuel pressure) of the fuel located upstream of the injector X is maintained at a constant value between 250 kPa and 400 kPa, for example, around 250 kPa. You. As described above, by maintaining the fuel pressure at a high pressure, generation of vapor at high temperatures or the like is suppressed, and atomization of the fuel spray injected from the injector 3 is performed.

Moreover, the electronically controlled fuel injection device, Rubeku to detect the state of the engine 1 as appropriate, engine rotation speed sensor 1 0, a water temperature sensor 1 1, 0 ₂ sensor 1 2, the intake pressure sensor 1 3, slot Torusensa 1 4, It is equipped with an air flow sensor 15 and an air temperature sensor 16, etc. Based on a signal indicating the state of engine 1 detected by these sensors, a control unit (ECU) with an electronic circuit is provided. 17) Calculates the optimal fuel injection amount and injection timing at each time and transmits them to the injector 3. As a result, the injection amount and the injection timing of the fuel from the injector 3 are optimally controlled according to the operating state of the engine 1.

On the other hand, an engine with a relatively small displacement mounted on a motorcycle or an equivalent vehicle or other driving device, for example, an engine with a displacement of approximately 50 cc to 250 cc per cylinder, emits exhaust gas. Because regulations were not so strict, fuel supply systems using carburetors have been adopted.

By the way, as part of the recent efforts to prevent global warming and protect the environment, it has become necessary to reduce emissions of carbon dioxide, nitrogen oxides, etc. due to reduced fuel consumption, even in engines with such small emissions. I have. Therefore, the existing electronically controlled fuel injection device is applied instead of the conventional cable breaker, It is conceivable that optimal fuel injection will be performed as in the case of a vehicle engine with a large capacity. .

However, when the above-described conventional electronically controlled fuel injection device is applied to an engine with a small displacement as it is, the following problems occur. First, when injecting high-pressure fuel from the injector 3 by opening and closing the solenoid valve by pulse drive, for example, the practical minimum injection amount per practical minimum pulse width at 250 kPa those of about 2-2. against 2 mm ³ of a Z pulse, 1 exhaust per cylinder low emissions, for example 5 0 cc minimum injection amount required by the displacement of the engine before and after is about 1 mm ³ about Bas Angeles. Therefore, it is difficult to adapt to the engine with small displacement while keeping the practical minimum injection amount in the conventional high pressure fuel injection.

Second, the circumferential flow type fuel pump 5 has a relatively large and complicated structure including a pump section, a motor section, and the like. The fuel tank 4 will be placed inside the fuel tank 4, which means that it is not suitable for motorcycle engines that have restrictions on the shape and size of the fuel tank.

Third, since the fuel feed pipe 7 from the fuel pump 5 to the injector 3 is filled with high-pressure fuel, it is desirable from the viewpoint of safety in a motorcycle engine in which overturning or the like must be considered. Not something.

Fourth, in the conventional system that supplies fuel at high pressure, the power consumption of the fuel pump 5 itself is large, and it is necessary to recirculate a large amount of fuel through the fuel pressure regulator 8. Power consumption will increase further. Therefore, it is not preferable for a small-displacement engine that requires a reduction in power consumption due to a limited supply power. Fifth, conventional systems that supply fuel at high pressure require high pressure resistance. And cost is generally high, including material costs for components and high quality control during manufacturing. Therefore, it is not preferable for a small displacement engine for which low cost is desired.

The present invention has been made in view of the above-mentioned problems of the prior art, and aims to reduce power consumption, cost, size, and space by lowering the fuel pressure. It is possible to supply the required small amount of fuel to a small displacement engine, for example, a small displacement engine mounted on a motorcycle, etc., and to achieve an optimal combustion state through fine control. An electronic control fuel injection device is provided. Disclosure of the invention

An electronic control fuel injection device according to the present invention includes a solenoid valve driven injector that injects fuel into an intake passage of an engine, a fuel pump that pumps fuel in a fuel tank toward an injector, and a fuel pump. A flow control type fuel pressure regulator that recirculates fuel toward the fuel tank while adjusting the pressure of fuel guided to the injector, and a control that issues a control signal to at least the injector based on engine operation information An electronically controlled fuel injection device comprising: a fuel pump, wherein the fuel pump is a positive displacement plunger pump for pumping a predetermined volume of fuel by a plunger reciprocally driven by an electromagnetic force as a driving source; One of the features is that it is an inlet control type regulator that controls the amount of fuel inflow on the upstream side of the sector. To have.

According to this configuration, when a predetermined drive signal is issued from the control means to the plunger pump, the generated electromagnetic force activates the plunger pump to pump a predetermined amount of fuel at a relatively low pressure. The fuel pumped at a low pressure has a predetermined low pressure, for example, 50 kP, by an inlet control type regulator. The pressure is adjusted to about a and supplied to the upstream of the injector. On the other hand, when a predetermined drive signal is issued from the control means to the injector, the solenoid valve is actuated at a desired timing for a desired time, so that a desired (for example, a small amount) of fuel enters the intake passage. Injected toward.

In other words, a small amount of fuel, for example, about 1.0 mm ³ / "pulse" can be supplied to a small displacement engine by low-pressure injection of, for example, about 50 kPa.

Further, the electronically controlled fuel injection device of the present invention includes a solenoid-valve-driven injector that injects fuel into an intake passage of an engine, a fuel pump that pumps fuel in a fuel tank toward the injector, and a fuel pump. And a control means for issuing a control signal to at least the injector based on operation information of the engine, based on a flow control type fuel pressure regulator that recirculates the fuel toward the fuel tank while adjusting the pressure of the fuel guided from the fuel injector to the injector. An electronically controlled fuel injection device, wherein the fuel pump is a positive displacement plunger pump for pumping a predetermined volume of fuel by a plunger reciprocated using an electromagnetic force as a drive source, and the fuel pressure regulator includes an injector. An outlet control regulator that controls the amount of recirculated fuel on the downstream side. It is characterized in that.

According to this configuration, when the control unit issues a predetermined drive signal to the plunger pump, the generated electromagnetic force activates the plunger pump to pump a predetermined amount of fuel at a relatively low pressure. The fuel pumped at a low pressure is supplied to the upstream of the injector, and the pressure is adjusted to a predetermined low pressure, for example, about 50 kPa by an outlet control type regulator. On the other hand, when a predetermined drive signal is issued from the control means to the injector, the solenoid valve operates at a desired timing for a desired time, and a desired (for example, a small amount) of fuel is supplied to the intake passage. It is injected toward inside. That is, a small amount of required fuel, for example, about 1.0 mm ³ Z pulse can be supplied to a small displacement engine by low pressure injection, for example, about 50 kPa.

In the above configuration, it is possible to adopt a configuration in which an accumulator for absorbing pulsation of fuel in the fuel passage from the fuel pump to the injector X is provided. According to this configuration, the pulsation in the fuel passage generated by driving the plunger pump is suppressed or completely absorbed by the accumulator, and the fuel with a more stable pressure is supplied to the upstream of the injector.

In the above configuration, as the plunger pump, a cylinder forming a fuel passage, and a fuel passage disposed in close proximity to the passage of the cylinder and reciprocally movable within a predetermined range and penetrating in the reciprocating direction are provided. A plunger, a first tic valve urged to close the fuel passage of the plunger and arranged to open the fuel passage by the forward movement of the plunger, and both ends of the plunger supported by the cylinder. And a pair of elastic bodies that urge each other in the reciprocating direction, and a plunger that is also arranged downstream of the fuel flow direction and is urged so as to close the passage of the cylindrical body and the plunger. Adopts a structure that has a second check valve arranged to open the passage of the cylinder by the return operation, and a solenoid coil that applies electromagnetic force to the plunger. It is possible.

According to this configuration, when the plunger starts the forward operation by the exciting action of the solenoid coil from the rest position held at a predetermined position in the cylinder by the pair of elastic bodies, the first check valve moves the fuel passage of the plunger. When released, fuel is drawn behind the plunger, ie, downstream. When the plunger that has reached the predetermined position starts the reverse operation in the reverse direction, the first check valve closes the fuel passage, and the second check valve closes the cylinder. Open the passage. As a result, the fuel is pumped toward the engine at a relatively low pressure.

In the above configuration, the solenoid coil is energized only during the forward operation of the plunger, and the pair of elastic bodies has the upstream volume on which the elastic body on the side that opposes the forward operation of the plunger is disposed, while the other elastic body has the other elastic body. Can be adopted such that it is set to be larger than the downstream volume in which is disposed. According to this configuration, when the plunger performs the forward operation by the excitation action of the solenoid coil, the plunger thereafter starts the reverse operation by the biasing force of one elastic body, and the same fuel pumping as described above is performed. Is performed. In this case, since the plunger performs the return operation only by using the biasing force of the elastic body, the power consumption is reduced.

In the above configuration, the accumulator can adopt a configuration formed integrally with the fuel pressure regulator.

According to this configuration, the pulsation of the fuel in the fuel passage from the plunger pump to the injector and the fuel pressure regulator is more effectively suppressed or completely absorbed by the accumulator arranged near the fuel pressure regulator. . In addition, the device can be formed compact by being integrally formed.

In the above configuration, the fuel pressure regulator is: Inge :! : It is possible to adopt a configuration which is directly coupled to the cubic unit and has a vapor separating means for separating the vapor in order to prevent the vapor of the fuel from entering the above-mentioned injector.

According to this configuration, the fuel pressure is maintained at a more stable and constant value near the upstream of the injector, and even if vapor is generated due to the low pressure, the vapor separating means operates, This prevents the vapor from entering the injector. Therefore, the desired fuel from the injector Is injected.

In the above configuration, it is possible to adopt a configuration in which the injector is arranged so as to inject fuel in a direction substantially orthogonal to a direction in which the intake passage of the engine extends.

According to this configuration, the fuel is injected from a direction substantially perpendicular to the flow of the intake air, so even if the fuel is injected at a relatively low pressure, the fuel collides with the flow of the intake air and is disturbed, so that the fuel is sprayed. Atomization is promoted.

In the above configuration, it is possible to adopt a configuration in which the injector is arranged at a position on the upstream side of an intake passage separated from the intake valve of the engine by a predetermined distance.

According to this configuration, since the fuel injection position is separated from the intake valve by a predetermined distance, when the injected fuel moves during this time, the fuel is heated from the intake manifold or the like forming the intake passage. The effect, that is, the riser effect, promotes fuel atomization. In addition, as a result, since the injector is separated from the engine, the generation of vapor in the fuel passage and the inside of the fuel tank due to heat directly received from the engine is suppressed.

In the above configuration, it is possible to employ a configuration in which a throttle body that forms a part of an intake passage of the engine and has a throttle valve that opens and closes the intake passage is provided, and is directly attached to the injector force and the throttle body. it can.

According to this configuration, the throttle pod and the injector are modularized, and when the fuel pressure regulator is directly connected to the injector, the throttle pod, the injector, and the fuel pressure regulator are modularized. Easy to do.

In the above configuration, it is possible to adopt a configuration in which the plunger pump is driven by resonance by the control means. According to this configuration, the driving frequency of the plunger matches the resonance frequency of the mechanical vibration system, and the pump is driven efficiently. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic configuration diagram showing the overall configuration of an electronically controlled fuel injection device of the present invention. FIG. 2 is a cross-sectional view showing a schematic configuration of a plunger pump constituting a part of the electronically controlled fuel injection device according to the present invention. Fig. 3 shows the characteristics of the plunger pump shown in Fig. 2. Fig. 3 (a) shows the relationship between the plunger stroke and thrust at a given current value, and Fig. 3 (b) shows the current value and Fig. 3 (c) is a diagram showing the relationship between the plunger stroke and the current value and the thrust. FIGS. 4 (a) and 4 (b) are partial sectional views showing other embodiments of the plunger pump, respectively. FIG. 5 is a cross-sectional view showing a schematic configuration of an outlet control type regulator that forms a part of the electronically controlled fuel injection device according to the present invention. FIG. 6 shows an embodiment in which vapor separating means is used for the outlet-control type regulator shown in FIG. 5, and FIG. 6 (a) shows an embodiment in which a space is secured as the vapor separating means. FIG. 6B is a partial sectional view showing an embodiment in which a guide plate is employed as a vapor separating means. FIG. 7 is a cross-sectional view showing a schematic configuration of an inlet control type regulator constituting a part of the electronically controlled fuel injection device according to the present invention. FIG. 8 is a cross-sectional view showing an arrangement structure of the injector X constituting a part of the electronically controlled fuel injection device according to the present invention. FIG. 9 is a schematic configuration diagram showing the entire configuration of a conventional electronically controlled fuel injection device. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing an embodiment of an electronically controlled fuel injection device according to the present invention. It is a block diagram. As shown in FIG. 1, the electronically controlled fuel injection device according to this embodiment includes a solenoid-valve-driven injector 30 that injects fuel into an intake passage of an engine 20, and a fuel in a fuel tank 40. An electromagnetic solenoid type plunger pump 50 as a fuel pump for pressure feeding, and recirculation of fuel toward the fuel tank 40 while adjusting the pressure of fuel guided from the plunger pump 50 to the injector 30 The basic configuration of a flow control type fuel pressure regulator 80 and a control unit (ECU) 103 as control means for issuing a control signal to the injector 30 etc. based on operating information of the engine 20, etc. Have.

In addition, as another configuration, as a sensor for detecting the operation state of the engine 20, a rotation speed sensor 100 for detecting the rotation speed of the crankshaft 21 and a temperature of the cooling water of the engine 20 are detected. Water temperature sensor 101, pressure sensor 102 that detects the pressure of intake air in the intake passage, and throttle chamber 1 1 that is connected to the intake manifold 22 and forms part of the intake passage 22a. It has a throttle opening sensor 120 and the like for detecting the opening of the throttle valve 111 at 0.

In addition to the above components, a 0 ₂ sensor for detecting the amount of oxygen in the exhaust Ma second inner hold, air flow sensor for detecting the air flow rate in the intake passage, an intake air temperature sensor for detecting the temperature of the intake air in the intake passage channel (either May also be provided).

Here, the fuel path will be described. The fuel tank 40 and the injector 30 or the fuel pressure regulator 80 are connected by a fuel feed pipe 130, and in the middle of the fuel feed pipe 130. The low pressure filter 140 and the plunger pump 50 are connected in an in-line manner from the upstream side.

Therefore, the fuel filter 41 and the low-pressure filter disposed in the fuel tank 40 are provided. The fuel that has passed through the filter 140 is pumped by the plunger pump 50 and supplied to the fuel pressure regulator 80 and the injector 30.

The delivery pipe (not shown) is formed integrally with the fuel pressure regulator 80.

Further, the fuel pressure regulator 80 and the fuel tank 40 are connected by a fuel return pipe 150, and the remaining fuel other than the fuel injected by the injector 30 is used for this fuel return. It is returned to the fuel tank 40 via the pipe 150.

As described above, by adopting the plunger pump 50 that can be arranged in-line as a fuel supply system, when applied to an engine mounted on a motorcycle or the like, the degree of freedom in layout or design is increased. Since the fuel tank and the like can be diverted as they are, the overall cost can be reduced.

Here, the plunger pump 50 will be described. This fuel pump is an electromagnetically driven positive displacement pump. As shown in FIG. 2, a core 52 is connected to the outer periphery of a cylindrical cylinder 51 as a cylindrical body. A solenoid coil 53 is wound around the outer periphery of the core 52. A plunger 54 as a movable body having a predetermined length is closely inserted into the inside of the cylinder 51, and is slidable in the axial direction inside the cylinder 51 so as to be reciprocally movable. .

The plunger 54 has a fuel passage 54 a penetrating in the reciprocating direction (axial direction), and has a fuel passage 54 a at one end thereof (downstream in the fuel flow direction). An expanded portion 54b is formed by enlarging in the radial direction. The first check valve 59 and the third coil spring 60 that urges the first check valve 59 toward the upstream side, that is, toward the fuel passage 54a are arranged in the extension portion 54b. And this extension 5 4 A stopper 54c, which forms a part of the plunger 54 and has a fuel passage in the center, is fitted to the outer end of the b. One end of the third coil spring 60 is connected to the end face of the stopper 54c. The side is held.

That is, the fuel passage 54 a of the plunger is always closed by the first check valve 59 urged by the third coil spring 60, and the space on both sides of the first check valve 59 is sandwiched. When a pressure difference of more than a predetermined value (pressure on the fuel passage 54 a side> pressure on the expansion portion 54 b side) occurs between the (fuel passage 54 a and the expansion portion 54 b), the first check valve 59 is fired. The passage 54a is opened. The first check valve 59 is not limited to a hemispherical one as shown in the figure, but may be a spherical one or a disk-like one, and the material may be rubber or steel. A first support member 55 and a second support member 56 are mounted on both ends of the cylinder 51, respectively, so that the first support member 55 and one end of the plunger 54 are provided between the first support member 55 and one end of the plunger 54. The first coil spring 57 is disposed, and the second coil spring 58 is disposed between the second support member 56 and the other end of the plunger 54. The first coil spring 57 and the second coil spring 58 form a pair of elastic bodies that urge the two ends of the plunger 54 to oppose each other in the reciprocating direction.

The first support member 55 is formed as a cylindrical body having a radially extending flange portion 55a, defines a fuel passage 55b therein, and has an annular shape formed on the outer peripheral surface thereof. The ring 61 is attached to the groove, and the flange 55a is brought into contact with the groove 61 so as to be fitted to the cylinder 51.

The second support member 56 is formed as a tubular body having a flange portion 56a, and an outer tubular portion 56c defining a fuel passage 56b therein. And an inner cylindrical portion 56d fitted to the outer cylindrical portion 56c. This outer tubular part 5 6 c 6a is in contact with the end of the cylinder 51 and fitted into the cylinder 51.

A reduced diameter portion 56e is formed inside the outer cylindrical portion 56c, and a second coil spring 58 is in contact with one end surface thereof. Further, a reduced diameter portion 56 f is formed inside the inner cylindrical portion 56 d, and is defined by an inner end surface of the reduced diameter portion 56 f and the other end surface of the reduced diameter portion 56 e. In the space, a disc-shaped second chuck valve 62 and a fourth coil spring 63 for urging the second chuck valve 62 toward the upstream side, that is, toward the reduced diameter portion 56 e are arranged.

That is, the fuel passage 56 b is always closed by the second check valve 62 urged by the fourth coil spring 63, and is provided in the space on both sides of the second check valve 62. When a pressure difference equal to or more than a predetermined value (upstream pressure> downstream pressure) occurs, the second tick valve 62 opens the fuel passage 56b. The second check valve 62 is not limited to a disk-shaped one as shown in the figure, but may be a hemispherical one or a spherical one, and the material may be rubber or steel.

Further, an outer core 65 is connected to the outside of the first support member 55 via an annular ring 64, and the outer core 65 has a fuel passage 65 a that penetrates in the axial direction. An inlet pipe 66 is fitted in the outer region. Further, an outer core 68 is connected via an o-ring 67 so as to surround the second support member 56 and the cylinder 51, and the outer core 68 has a fuel penetrating in the axial direction. A passage 68 a is formed, and an outlet pipe 69 is fitted in an outer region thereof.

In the above configuration, the inner passage of the inlet pipe 66, the fuel passage 65a of the outer core 65, the fuel passage 55b of the first support member 55, and the cylinder 51 The fuel passage 54 of the plunger 54, the fuel passage 56 of the second support member 56, the fuel passage 68 of the outer core 68, and the internal passage of the outlet pipe 69 as a whole. Are formed.

Further, in the above configuration, in a rest state where the solenoid coil 53 is not energized, the plunger 54 is positioned at a position where the biasing forces of the first coil spring 57 and the second coil spring 58, which oppose each other, are balanced. (The rest position shown in FIG. 2), and an upstream space S u including the first coil spring 57 and a downstream space S d including the second coil spring 58 are defined. Here, the length and the spring constant of the first coil spring 57 and the second coil spring 58 are such that, in the rest state, the upstream space S u in which the first coil spring 57 is arranged is the second coil spring. It is set to be larger than the downstream space Sd where the spring 58 is arranged.

In the idle state, when the solenoid coil 53 is energized and an electromagnetic force is generated, the plunger 54 is drawn toward the upstream side (toward the left side in FIG. 2) and starts the forward operation. At this time, the upstream space S u is reduced, while the downstream space S d is expanded. However, since the second check valve 62 blocks the fuel passage 56 b, the downstream space S d is reduced. Pressure drops. Then, when the pressure of the upstream space Su becomes larger than the pressure of the downstream space Sd by a predetermined value or more, the first check valve 59 resists the urging force of the third coil spring 60. Open fuel passage 54a. Thereby, the fuel in the upstream space Su is sucked into the downstream space Sd through the fuel passage 54a.

Then, when the plunger 54 has moved a predetermined distance, the energization of the solenoid coil 53 is released and the forward operation is completed, or the energization is immediately released after the instantaneous energization to start the operation. The first coil When the forward movement of the plunger 54 is completed due to the balance with the biasing force of the spring 57, the first check valve 59 simultaneously closes the fuel passage 54a. Subsequently, the plunger 54 starts the return operation toward the downstream side (toward the right side in FIG. 2) by the urging force of the first coil spring 57 increased by the compression. Due to the return operation of the plunger 54, the fuel sucked into the downstream space Sd starts to be compressed, and when a predetermined pressure is reached, the fuel is pressed against the urging force of the fourth coil spring 63. 2 Tick valve 62 opens fuel passage 56 b. Thereby, the fuel filled in the downstream space Sd is discharged at a predetermined pressure through the outlet pipe 69.

As described above, when the plunger 54 is driven, the solenoid coil 53 is energized only during the forward operation, and the return operation is performed by releasing the spring energy stored by the compression of the first coil spring 57. Power consumption can be reduced because of non-energized discharge (spring delivery).

Since both ends of the plunger 54 are supported by the first coil spring 57 and the second coil spring 58, it is possible to prevent the plunger 54 from hitting due to a collision.

The driving method of the plunger pump 50 is not limited to the above non-energized discharge.

Alternatively, energization and discharge may be performed to energize the solenoid coil 53 to make the plunger 54 return. Since there is no time lag with respect to the drive pulse, this energized discharge is preferable in the case of a supply system that emphasizes responsiveness. Note that when performing this discharge, the relationship between the plunger 54, the first coil spring 57, and the second coil spring 58 shown in FIG. 2 is such that the first coil spring 57 is arranged in the rest state. The upstream space S u force is smaller than the downstream space S d in which the second coil spring 58 is arranged, that is, the plunge on the left side in FIG. The key 54 is set to be located.

As a driving method of the plunger pump 50, for example, constant voltage falling control and pulse driving near 40 Hz can be adopted.The frequency of this pulse driving matches the resonance frequency of the mechanical vibration system. Then, by performing the resonance drive, the pump efficiency can be improved.

It is also possible to employ constant current control or overexcitation control. In this case, the pump can be driven at a higher frequency, so that the pump discharge amount can be increased and the pulsation of the discharged fuel can be reduced. be able to. Furthermore, by controlling the driving frequency or the current value when driving the plunger pump 50 between when the engine 20 starts and after the engine 20 starts, the control is performed separately.

However, the start-up time can be made faster to shorten the start-up time.

As a characteristic of the plunger pump 50, the relationship of the thrust to the stroke of the plunger 54 when the current value is changed is shown in FIG. 3 (a), and the relationship of the stroke (discharge amount) to the current value is shown in FIG. In (b), the relationship between the current value and the thrust (discharge pressure) is shown in Fig. 3 (c). That is, since the stroke (discharge amount) and thrust (discharge pressure) of the plunger 54 are linearly proportional to the current value flowing through the solenoid coil 53, the current value is appropriately changed or changed. Thereby, the fuel discharge amount and the fuel discharge pressure can be freely adjusted as needed.

FIG. 4 shows another embodiment of the plunger pump 50, in which the downstream space Sd region is particularly changed. That is, the plunger pump 50 ′ according to the embodiment shown in FIG. 4 (a) has an end portion of an outer cylindrical portion 56 c ′ that forms a spherical first check valve 59 ′ and a second support member 56 ′. The plunger pump shown in Fig. 2 except that a It has the same configuration as 50.

In this way, a convex end is formed on the second support member 56 so as to face the convex end of the plunger 54 (stop ring 54 c), and the second coil spring 58 is formed. By supporting the inner guides, the downstream space Sd, that is, the pump volume, can be optimized to increase the compression ratio, and sufficient self-sufficiency (self-priming) can be secured.

Further, the plunger pump 501 according to the embodiment shown in FIG. 4 (b) is different from that of the first embodiment in that a spherical first check valve 59 ′ is replaced by a pot-type first check valve 59 ′. Has the same configuration as the plunger pump 50 'shown in FIG. 4 (a).

With such a configuration, the compression ratio can be further increased by the space in which the pot-type first check valve 59 ′ is arranged, and the sufficient compression ratio can be obtained even at the first startup. Self-sufficiency can be secured.

When the plunger pumps 50, 50 ', and 50' '' as described above are employed, since particles such as brush abrasion powder of the motor do not occur as in the conventional case, the conventional pump downstream side is used. This eliminates the need for a certain high-pressure filter, thereby reducing the overall cost of the device.

As the fuel pressure regulator located downstream of the plunger pump 50, an outlet control type regulator 80 for controlling the amount of fuel recirculated downstream of the injector 30 or upstream of the injector 30 An inlet control type regulator 90 that controls the amount of fuel inflow at the side can be employed.

As shown in Fig. 5, the outlet-controlled type regulator (relief valve) 80 is a regulator body 81, a control valve 82, and a control valve 82 formed by molding aluminum or the like. A diaphragm 83 for controlling the opening and closing of the device is provided as a basic configuration. The regulator body 81 has a first space 81 a, a second space 81 b, a communication passage 81 c communicating the first space 81 a with the second space 81 b, and a second space 81 c. A column-shaped valve seat portion 8 1 d and a relief passage 8 1 e extending in the horizontal direction passing through the center of the valve seat portion 8 1 d in the axial direction at substantially the center of the space portion 8 1 a. ing. Further, on the side opposite to the first space portion 81a, a third space portion 81h and a communication passage 81k connecting the third space portion 81h to the first space portion 81 are formed. Have been.

In the first space portion 81a, a diaphragm 83 holding a control valve 82 is disposed, and a coil spring 84 is disposed outside the diaphragm 83. The coil spring 84 is compressed by a predetermined amount. A cap-shaped cover body 85 is coupled with the diaphragm 83 sandwiched therebetween. The cover body 85 is provided with a vent hole 85a, and an air chamber surrounded by the cover body 85 is opened to the atmosphere. The air chamber may be communicated with the intake manifold 22.

That is, the diaphragm 83 closes the first space portion 81a from above, and the upper end of the relief passage 81e of the valve seat portion 81d by the force of the control valve 82 and the biasing force of the coil spring 84. The opening is closed. The first space 81a forms a control chamber for controlling the fuel pressure.

In the second space 81b, an opening 81m is formed below the second space 81b, and the upper part of the injector 30 (fuel connector 32) is fitted into the opening 81m. It is like that. When this exit control type regulator 80 is used for a multi-cylinder engine, the delivery pipe can be formed by extending the second space portion 81b in the horizontal direction. That is, a delivery chamber for supplying fuel to the injector 30 is formed by the second space portion 81b. Further, a return pipe 81 f defining a return passage communicating with the relief passage 81 e and an inflow pipe 81gt defining an inflow passage communicating with the second space portion 81 b from the horizontal direction. It is press-fitted into body 81. The inflow pipe 81g is connected to the fuel feed pipe 130, and the return pipe 81f is connected to the fuel return pipe 150. Note that the return pipe 8If and the inflow pipe 8lg may be integrally formed with the regulator body 81.

Further, a diaphragm 86 is disposed from the outside in the third space portion 81h, and a coil spring 87 is disposed outside the diaphragm 86. The diaphragm 86 is compressed while compressing the coil spring 87 by a predetermined amount. In this way, a cap-shaped cover unit 8 8 is connected.

That is, the diaphragm 86 closes the third space portion 8lh from below, and the urging force of the coil spring 87 presses the diaphragm 86 inward with a predetermined pressure. The cover body 88 is provided with a vent hole 88a, and an air chamber surrounded by the cover body 88 is opened to the atmosphere. This air chamber may be communicated with the intake manifold 22.

The diaphragm 86, the third space 81h, and the communication passage 81k are provided with an accumulator (or silencer) for absorbing fuel pulsation in the fuel passage from the plunger pump 50 to the injector 30. ).

This accumulator suppresses or completely absorbs the pulsation of the fuel caused by the plunger pump 50, thereby suppressing the variation of the fuel injected from the injector 30. Vibration phenomena such as repeated hits of 8 Id can be prevented, and the durability of the device can be improved. In the outlet control type regulator 80 having the above configuration, when the relatively low-pressure fuel discharged from the plunger pump 50 is led to the inflow pipe 81 g via the fuel feed pipe 130, the second space From the section 81b to the injector Xta 30, it is also guided to the control room (first space section 81a) and the third space section 81h through the communication passage 81c.

Here, when the fuel pressure in the control room exceeds a predetermined level, the diaphragm 83 is pushed upward against the urging force of the coil spring 84, and the control valve 82 is moved to the upper end of the relief passage 81e. , And fuel starts to flow toward fuel tank 40. Then, when the pressure of the fuel in the control chamber drops to a predetermined level, the diaphragm 83 is urged again by the coil spring 84, and the control valve 82 closes the upper end of the relief passage 81e. As a result, the fuel pressure in the upstream region of the injector 30 is maintained substantially constant.

In the outlet control type regulator 80, since a relatively low-pressure fuel is supplied, the flow rate of the fuel returned to the fuel tank 40 is small, and the fuel is consumed as compared with the conventional high-pressure injection supplied at a high pressure. The power can be reduced.

Also, the pressure of the fuel in the control chamber fluctuates, and when the pressure exceeds a predetermined level, the diaphragm 86 is pushed outward against the urging force of the coil spring 87 to reduce the fuel pressure. Works. This effectively suppresses or absorbs fuel pulsation. In addition, since the accumulator including the diaphragm 86, the third space 81h, the coil spring 87, the cover 88, etc. is formed integrally with the fuel pressure regulator, the entire apparatus is formed. The compaction can be performed as follows. In the outlet control type regulator 80 having the above configuration, the fuel vapor is prevented from entering the injector 30 by separating the vapor. A separating means can be employed. FIG. 6 shows an embodiment employing this vapor separating means.

The outlet control type regulator 80 1 shown in FIG. 6 (a) is formed so as to be larger than the second space 8 1 b ′ of the second space 8 1 b ′ shown in FIG. The vapor that has entered from above or the vapor generated in the second space portion 8 1 b moves upward and passes through the communication passage 81 c into the control room. Thus, it is possible to prevent vapor generated in the fuel passage from entering or being sucked into the injector 30.

In the outlet control type regulator 80 shown in FIG. 6B, the second space 81b ′ is formed to be larger than the second space 81b shown in FIG. (2) A guide plate 89 with an L-shaped cross section is provided in the space 8 lb '', and especially the vapor that has entered through the inflow pipe 81 g is forcibly guided upward by this guide plate 89. As a result, the vehicle can pass through the communication passage 81c to the control room. Thereby, it is possible to more reliably prevent the vapor generated in the fuel passage from entering or being sucked into the injector 30.

On the other hand, as shown in Fig. 7, the inlet control type regulator (also referred to as a pressure reducing valve) 90 is a regular body 91, a disc valve 92, and a disc valve 9 formed by molding an aluminum material or the like. A push rod 93 and a diaphragm 94 for controlling the opening and closing of 2 are provided as a basic configuration.

The regulator body 91 includes a first space portion 91a, a second space portion 91b, a communication passage 91c communicating the first space portion 91a with the second space portion 91b, and a delivery. A third space 91d defining a room, a communication passage 91e connecting the third space 9Id to the second space 91b, and a return extending horizontally from the third space 91d. A passage 91 f is formed. This first space part 9 1 A fuel inlet pipe 91 g is press-fitted into the fuel feed pipe 130 and defines a fuel inlet passage.The fuel return pipe 150 is inserted into the return passage 9 If. The return pipe 9 1 h connected to is press-fitted. The inflow pipe 91 g and the return pipe 91 h may be integrally formed with the regulator body 91.

A support cap 95 having an opening 95a at a substantially central portion thereof is fixed to the first space portion 91a, and a coil spring 96 is disposed on the bottom surface thereof. Disc valve 92 is arranged above 96. The coil spring 96 urges the disk valve 92 upward so as to close the lower end opening 9lk of the communication passage 91c.

In the second space 91, a diaphragm 94 holding a push rod 93 that passes through the communication passage 91c and contacts the upper surface of the disc valve 92 is arranged, and a coil spring 97 is arranged outside the diaphragm. Then, a cap-shaped cover integral 98 is connected so as to sandwich the diaphragm 94 while compressing the coil spring 97 by a predetermined amount. The cover 98 is provided with a vent hole 98a, and an air chamber surrounded by the cover 98 is opened to the atmosphere. This air chamber may be connected to the inside of the intake manifold 22.

Further, in the second space portion 91b, a stopper 99 fitted to the communication passage 91c is provided so as to protrude by a predetermined height, and a diaphragm 94 is provided at an upper end portion of the stopper 99. The lower surface abuts to restrict the downward movement of the diaphragm 94, that is, the push rod 93, to a predetermined range.

An opening 9 lm is formed on the lower side of the third space 91 d, and the upper part (fuel connector 32) of the injector 30 is fitted into the opening 9 lm. . For a multi-cylinder engine, this exit control type When the gear 90 is used, the delivery pipe can be formed by extending the third space portion 91 d in the horizontal direction. That is, a delivery chamber for supplying fuel to the injector 30 is formed by the third space portion 91.

Inside the return pipe 91 h located downstream of the third space section (delivery chamber) 91 d, a check valve 91 n is directed toward the end of the return passage 91 f. An energizing coil spring 91P is provided, and an orifice 91r is disposed downstream thereof.

The above-mentioned chuck valve n 1 n plays a role of maintaining the residual pressure in the third space (delivery chamber) 91 d at a predetermined level in a state where the fuel is not supplied. Thereby, particularly when the engine is stopped and restarted at a high temperature, poor startability due to a vapor lock or the like can be improved and always good startability can be ensured. The orifice 91 r plays a role in regulating the flow rate for efficiently discharging generated fuel vapor.

In the inlet control type regulator 90 having the above configuration, the diaphragm 94 is normally pushed down by the urging force of the coil spring 97, and the push port 93 pushes the disc valve 92 downward. Therefore, the disc valve 92 opens the communication passage 91c, and the fuel guided into the first space 91a by the inflow pipe 91g passes through the communication passage 91c to the second space 91c. It flows into the space 91b, and is further led to the third space (delivery chamber) 9Id through the communication passage 91e.

On the other hand, when the pressure in the second space portion 9 1b exceeds a predetermined level, the diaphragm 94 is pushed upward against the urging force of the coil spring 97, and the push rod 93 also moves upward at the same time. I do. When the push rod 93 moves to a predetermined position, the disc valve 92 turns the coil switch. It is urged by the urging force of the spring 96 to close the lower end opening 91k of the communication passage 91c.

By performing the above series of operations with good responsiveness, pulsation of the fuel guided from the inflow pipe 91 g can be effectively reduced. If an accumulator that absorbs fuel pulsation is adopted upstream of the first space portion 91a, pulsation can be further reduced.

In the inlet control type regulator 90 having the above configuration, a rubber or steel spherical valve can be adopted instead of the disc valve 92, and instead of the disc valve 92 and the push rod 93, It is also possible to adopt a port valve type in which both are integrated.

In addition, similarly to the above-mentioned outlet control type regulator 80, it is of course possible to employ a vapor separating means as shown in FIG. 6 in the third space 91d. Thus, it is possible to prevent the vapor from entering or being sucked into the injector 30.

As described above, the injector 30, to which the fuel pressure regulators 80, 90 are directly connected, is a throttle body connected to the intake manifold 22 of the engine 20, as shown in FIG. Directly attached to 10. As shown in Fig. 8, the mounting position of the nozzle 30 is higher than the throttle valve 111 provided rotatably in the intake passage 112 of the throttle body 110. On the downstream side, the mounting direction is substantially perpendicular to the extension direction L of the intake passage 112, that is, from the direction substantially perpendicular to the flow of intake air in the intake passage 112. It is arranged so that fuel is injected.

With this arrangement, the fuel injected from the injector 30 collides with the flow of the intake air and is disturbed. Therefore, atomization of the spray is promoted even if the fuel is injected at a relatively low pressure. Also, since the injector 30 is mounted on the throttle body 110 connected to the upstream end of the intake manifold 22, as a result, the intake valve 23 of the engine 20 (see FIG. 1) ) Is located at a predetermined distance from the upstream of the intake passage.

This predetermined distance is substantially governed by the length of the intake passage 22a of the intake manifold 22. In selecting this dimension, in addition to the restrictions on the rate, the intake It is preferred that the heat release from the manifold 22 be long enough to transmit to the fuel spray passing through the inside.

With such a length, when the fuel injected into the intake passage 22 a moves, the fuel is atomized by the heating effect from the intake manifold 22, that is, the riser effect. Promoted.

The injector 30 is a solenoid valve driven type as shown in FIG.

A main body 31 having a substantially cylindrical shape; a fuel connector 32 located at one end of the main body 31; an electrical connector 33 provided on a connector 32 side of the main body 31; a tip 3 forming an injection portion 3 4 etc.

A fuel passage 31 a is formed inside the main body 31, and a fixed iron core 35 is disposed substantially at the center, and a solenoid coil 36 is wound therearound. Further, a return spring 37 is arranged in a substantially intermediate region in the fuel passage 31a, and a movable iron core 38 is arranged reciprocally downstream of the return spring 37.

A needle valve 39 is formed integrally on the downstream side of the movable iron core 38, and a valve portion 39a of the needle valve 39 abuts against a valve seat of the fuel passage 31a. The fuel passage 31a is opened and closed by separating the fuel passage 31a. In addition, an injection port 34a is formed at the end of the tip section 34 surrounding the valve section 39a and the like, and fuel is injected from the injection port 34a. You.

That is, the fuel supplied from the fuel connector 32 side passes through the filter, passes through the fuel passage 31a, and is filled up to immediately before the upstream of the valve portion 39a. In this state, when a signal is sent from the control unit 103 via the electrical connector 33 and the solenoid coil 36 is energized, an electromagnetic force is generated and the biasing force of the return spring 37 is generated. The movable iron core 38 is lifted against it. At the same time, the needle valve 39 also moves upward, and the valve section 39a opens the fuel passage 3la. As a result, fuel at a predetermined pressure and a predetermined flow rate is injected from the injection port 34a.

On the other hand, when the power to the solenoid coil 36 is cut off, the movable iron core 38 is returned by the urging force of the return spring 37, and the valve portion 39a closes the fuel passage 31a.

The operation of the electronically controlled fuel injection device having the above configuration will be described below. First, the control unit 10 is operated based on the detection signals from the rotational speed sensor 100, the water temperature sensor 101, the pressure sensor 102, the throttle opening sensor 120, etc., which detect the state of the engine 20. When a signal is sent from 3 to the plunger pump 50, the plunger 54 is pulsed at, for example, 40 Hz. The fuel that has passed through the fuel tank 40, the fuel filter 41, and the low-pressure filter 140 is discharged from the plunger pump 50 at a relatively low pressure.

The discharge pressure at this time is set so that the fuel pressure upstream of the injector 30 is about 30 kPa to about 100 kPa. If the pressure is smaller than 300 kPa, fuel vapor is likely to be generated. Therefore, a value higher than 100 kPa is preferable as the limit of the gas generation. Since it becomes impossible to use a simple pipe having a low pressure resistance as one diode 130 or the like, a lower limit of the pressure resistance of the pipe or the like is preferable. Then, the fuel guided to the fuel pressure regulators 80 and 90 through the fuel feed pipe 130 is appropriately adjusted to a desired pressure, and the pulsation of the fuel is absorbed. In this state, when a signal is sent from the control unit 103 to the injector 30, the solenoid valve (needle valve 39) of the injector 30 is opened, and the intake air in the intake passage 112 is opened. Fuel is injected into the intake passage 112 from a direction substantially perpendicular to the flow of the fuel.

The injected fuel is disturbed by the collision with the intake air to promote atomization, and furthermore, the atomization is promoted by the riser effect when passing through the intake manifold 22. As a result, the fuel whose atomization and atomization have been promoted is guided into the combustion chamber of the engine 20 together with the intake air, thereby producing favorable combustion.

On the other hand, the fuel other than the fuel injected by the injector 30 is returned to the fuel tank 40 from the return pipes 8 lf and 91 h of the fuel pressure regulators 80 and 90 via the fuel return pipe 150 and the fuel return pipe 150. It will be refluxed. Since the returned fuel flow is also small, the power consumption of the entire system is reduced.

In the above-described embodiment, only the electromagnetically driven and positive displacement type plunger pump 50 is shown as the fuel pump. However, the electromagnetically driven and positive displacement type diaphragm pump is assumed to be capable of discharging fuel at a relatively low pressure. Alternatively, a rotary displacement roller vane pump can be employed.

In addition, a motorcycle equipped with a small displacement engine is described here as an example.However, the invention is not limited to this. Carts for tricycles or four-wheeled vehicles, lawn mowers, and generators The present invention can be preferably applied to a general-purpose engine such as a boat, a boat such as a leisure boat, a snowmobile, and the like, which are equipped with a small-displacement engine. Industrial applicability

As described above, according to the electronically controlled fuel injection device of the present invention, the combination of the electromagnetically driven plunger pump and the fuel pressure regulator of the inlet control or the outlet control allows, for example, about 50 cc per cylinder. A small displacement engine can be injected with the required small amount of fuel.

Further, since the pressure in the entire supply system is low and the flow rate of the fuel recirculated from the fuel pressure regulator is small, the power consumption as a whole can be reduced.

In addition, since the plunger pump can be arranged in-line, the degree of freedom in layout and design is increased.Especially, when mounted on a motorcycle, etc., a compact arrangement structure is achieved while diverting the conventional fuel tank. be able to.

Furthermore, because the plunger pump is a low-pressure discharge plunger, a low-pressure filter used in a system using a calibrator can be applied without using a conventional high-pressure filter, and a pressure-resistant structure is required. Therefore, the supply system as a whole can be reduced in weight, size and cost by simplifying the piping and making the piping material thinner.

Furthermore, by adopting vapor separating means, and by mounting the injector so as to be substantially perpendicular to the intake passage or upstream of the intake passage separated from the intake valve of the engine, the inside of the fuel passage and the injector can be removed. Thus, the generation of vapor can be suppressed, and the atomization and atomization of the injected fuel can be promoted.

Claims

The scope of the claims

1. An electromagnetic valve driven injector that injects fuel into the intake passage of the engine, a fuel pump that pumps fuel from the fuel tank toward the injector, and regulates the pressure of fuel guided from the fuel pump to the injector. An electronically controlled fuel injection device comprising: a flow control type fuel pressure regulator that recirculates fuel toward a fuel tank while performing control; and a control unit that issues a control signal to at least an injector based on engine operation information.

The fuel pump is a positive displacement plunger pump that pumps a predetermined volume of fuel by a plunger that reciprocates using electromagnetic force as a driving source.

An electronically controlled fuel injection device, characterized in that the fuel pressure regulator is an inlet control type regulator that controls a fuel inflow amount on an upstream side of the injector.

2. A solenoid valve-driven injector that injects fuel into the intake passage of the engine, a fuel pump that pumps fuel from the fuel tank toward the injector, and a fuel pressure that is guided from the fuel pump to the injector. An electronically controlled fuel injection device comprising: a flow control type fuel pressure regulator that recirculates fuel toward a fuel tank; and control means that issues a control signal to at least an injector based on engine operation information.

The fuel pump is a positive displacement plunger pump that pumps a predetermined volume of fuel by a plunger that reciprocates using an electromagnetic force as a drive source, and the fuel pressure regulator is recirculated downstream of the injector. An electronically controlled fuel injection device, which is an outlet control type regulator for controlling a fuel outflow amount.

3. An accumulator for absorbing pulsation of fuel in a fuel passage from the fuel pump to the injector X is provided. Item 3. An electronically controlled fuel injection device according to item 1 or 2.

4. The plunger pump comprises: a cylinder forming a fuel passage; and a plunger having a fuel passage which is arranged in close proximity to the passage of the cylinder so as to reciprocate within a predetermined range and penetrates in the reciprocating direction. A first check valve urged to close the fuel passage of the plunger and disposed so as to open the fuel passage by the forward movement of the plunger; and both ends of the plunger supported by the cylindrical body. And a pair of elastic bodies that urge each other in the reciprocating direction, and the plunger is also disposed downstream of the fuel flow direction and is urged to close the passage of the cylindrical body. And a second tick valve arranged to open the passage of the cylindrical body by the return operation of the plunger, and a solenoid coil for applying an electromagnetic force to the plunger. Electronically controlled fuel injection device according to 3 or claims 1, characterized in that.

5. The solenoid coil is energized only during the forward operation of the plunger, and the pair of elastic bodies has an upstream volume on which the elastic body on the side that opposes the forward operation of the plunger has the other volume. 5. The electronically controlled fuel injection device according to claim 4, wherein the volume is set to be larger than the downstream volume in which the elastic body is disposed.

6. The electronically controlled fuel injection device according to claim 3, wherein the accumulator is formed integrally with the fuel pressure regulator.

7. The fuel pressure regulator is directly connected to the injector, and has a vapor separating means for separating the vapor so as to prevent fuel vapor from entering the injector. The electronically controlled fuel injection device according to any one of claims 1 to 6, wherein:

8. The injector is characterized in that the injector is arranged so as to inject fuel in a direction substantially perpendicular to a middle direction of an intake passage of the engine. The electronically controlled fuel injection device according to any one of claims 1 to 7.

9. The electronically controlled fuel according to any one of claims 1 to 8, wherein the injector X is disposed at a position upstream of an intake passage at a predetermined distance from an intake valve of an engine. Injection device.

10. A throttle body that forms a part of an intake passage of the engine and has a throttle valve that opens and closes the intake passage.

The electronically controlled fuel injection device according to any one of claims 1 to 9, wherein the ink injector is directly attached to the throttle body.

11. The electronically controlled fuel injection according to any one of claims 1 to 10, wherein the plunger pump is driven by resonance by the control means.