JP5367024B2 - Fuel supply device - Google Patents

Description

  The present invention relates to a fuel supply device that supplies fuel to a fuel injection device of an internal combustion engine, for example.

  The piston type fuel pump disclosed in Patent Document 1 or 2 includes a cylinder having a swash plate driven by an electric motor and a plurality of pistons reciprocated by the rotation of the swash plate. A suction port is provided for introducing fuel into the pressurizing chamber.

JP 2009-108683 A JP 2011-26962 A

In this type of fuel supply device, a swirling flow tends to occur in the fuel in the pump due to the rotation of the motor rotor and the swash plate, and the fuel before being sucked into the intake port of the cylinder is swirled. It causes vortex generation due to fluid friction accompanying flow.
Alternatively, the fuel is disturbed by the reciprocating motion of the piston or the return spring that urges the return force of the piston. These all increase pressure loss, and vapor (bubbles) are likely to be generated in the fuel.
Furthermore, the swirl flow formed almost parallel to the cylinder end face is in a direction perpendicular to the suction port, so the fuel sucked into the suction port is abruptly bent in the flow direction from the swirl flow to the right angle. It will be sucked into the port, causing an increase in pressure loss.
In particular, when the temperature of the fuel becomes high, the generation of vapor increases due to the highly volatile fuel.

  The present invention has been made to solve the above-described problems, and provides a fuel supply device that suppresses the influence of swirling flow in the vicinity of the intake port, reduces fuel intake pressure loss, suppresses vapor intake, and the like. The purpose is to provide.

The present invention provides a fuel supply device that drives a pump unit by a motor unit and pressurizes and discharges fuel sucked by the pump unit. The pump unit includes a housing having a suction nipple and a discharge nipple, and a housing in the housing. A cylinder in which a plurality of pistons are accommodated, an inclined plate that is provided on a shaft of the motor unit and reciprocates the plurality of pistons, and passes through the cylinder in an axial direction corresponding to the pistons. And a plurality of suction ports serving as fuel passages for guiding the fuel to the pressure increasing chamber, and both ends of the cylinder and the motor portion are fitted and held, and the fuel sucked from the suction nipples is supplied to the plurality of suction ports. comprising a substantially cylindrical bush for guiding the suction port and the piston is to be positioned in different space partitioned from each other It is those that you configured.

  According to the present invention, a fuel supply device that can reduce the fuel suction pressure loss, suppress the vapor suction, prevent the vapor from staying in the pump, stabilize the pump discharge amount, stabilize the control fuel pressure, etc. with a simple configuration. Can be obtained.

It is a block diagram which shows the fuel system which the fuel supply apparatus of this invention is used. It is principal part sectional drawing which shows the fuel supply apparatus of Embodiment 1 of this invention. FIG. 3 is a top view showing a cylinder in the first embodiment. FIG. 3 is a side view including a bush and a cylinder in the first embodiment. It is AA sectional drawing of FIG. It is BB sectional drawing of FIG. FIG. 6 is a characteristic diagram illustrating an example of pump discharge flow characteristics in the first embodiment. It is a top view which shows the bush in Embodiment 2 of this invention with a cylinder. It is CC sectional drawing of FIG. It is a top view which shows the bush in Embodiment 3 of this invention with a cylinder. It is DD sectional drawing of FIG. FIG. 10 is a cross-sectional view showing a positional relationship between a bush and a suction nipple in Embodiment 3. It is a top view which shows the bush in Embodiment 4 of this invention with a cylinder. It is EE sectional drawing of FIG. FIG. 10 is a cross-sectional view showing a positional relationship between a bush and a suction nipple in a fourth embodiment.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a fuel system in which the fuel supply apparatus of the present invention is used.
The fuel supply device 2 is driven by a drive signal from the control unit 5, and the fuel supply device 2 sucks and discharges fuel from the fuel tank 1 through a filter.
The discharged fuel is adjusted to a predetermined pressure by the pressure adjusting device 3, passes through the high-pressure fuel pipe, and is supplied to the fuel injection device 4.
The fuel injection device 4 controls the injection timing and the injection amount based on the drive signal from the control unit 5 based on the engine speed, the load, and the like, and injects the fuel into the intake pipe.

FIG. 2 is a structural diagram showing the fuel supply device 2 according to the first embodiment of the present invention. 3 is a top view of the cylinder in the first embodiment, FIG. 4 is a side view including the bush and the cylinder in the first embodiment, FIG. 5 is a cross-sectional view taken along the line AA in FIG. 4, and FIG. It is sectional drawing.
The fuel supply device 2 includes a motor unit 10 and a pump unit 20.
The motor unit 10 includes a stator and a rotor (not shown). A coil is wound around the stator, and a rotating magnetic field is generated by switching the excitation phase by a drive signal from the control unit 5.
The rotor is composed of a shaft, a magnet, and an inclined plate, and an inclined plate 12 is inclined at a predetermined angle and fixed to the tip of the shaft 11.
A cylindrical partition wall 13 is provided in the space between the stator and the magnet, and the stator and the coil are isolated from the fuel.

The pump unit 20 includes a housing 21 that is airtightly coupled to the motor unit 10 via the flange 13 a of the partition wall 13, and is coupled to the motor unit 10 by screws 22.
The housing 21 has a suction nipple 23 connected to the fuel tank 1 and a discharge nipple 24 connected to the fuel injection device 4.
In the housing 21, an inclined plate 12 fixed to the shaft end of the shaft 11 and rotating, a cylinder 26 in which a plurality of pistons 25 driven by the inclined plate 12 are disposed, and a spring that urges each piston 25. 27 is provided.
A plurality of piston holes 26a are arranged on the circumference of the cylinder 26 at an equal pitch, and a plurality of intake ports 26b serving as fuel passages for guiding fuel to the pressure increasing chamber are provided in pairs with the piston holes 26a. ing.

Further, in the housing 21, a cylindrical bush 28 is fitted and held between the stepped portion 26 c at the top of the cylinder 26 and the flange 13 a of the partition wall body 13 of the pump unit 20 with a gap from the inner wall of the housing 21. ing.
The bush 28 has an outer peripheral shape formed into a cylindrical shape by injection molding of a resin material, and a plurality of openings 28a for introducing fuel are provided on the outer peripheral surface, and the fuel flowing from the suction nipple 23 Is guided to the suction nipple 23 through the opening 28a and guided into the pump. The plurality of openings 28a are provided with nets for preventing intrusion of unnecessary objects.
The inner diameter side of the bush 28, between the suction port 26b and the pistons 25, a plurality of beam-like partition wall 28b is provided extending radially between the plurality of air-partitioning the respective intake ports 26b and the pistons 25 Is formed.
The partition wall 28b is disposed so that the piston 25 is located upstream of the suction port 26b with respect to the swirling flow of fuel in the rotational direction of the shaft 11 of the motor unit 10.

In such a configuration, the fuel flowing into the pump unit 20 from the suction nipple 23 causes the piston 25 to reciprocate in the axial direction by the inclined plate 12 rotated as the shaft 11 is rotated by the motor unit 10. Thus, each suction port 26 b is sent through the suction valve 29 to the pressure increasing chamber provided on the lower side of the piston 25 and pressurized, and is sent from the discharge nipple 24 through the discharge valve 30.
The suction valve 29 and the discharge valve 30 are composed of a thin metal plate having elasticity similar to the suction valve body and the discharge valve body shown in FIG. It is.

In the operation of the pump unit 20 as described above, the fuel in the vicinity of the piston 25 among the fuel riding on the swirling flow in the rotation direction of the shaft 11 of the motor unit 10 is separated from the suction port 26b by the partition by the partition wall 28b of the bush 28. Therefore, the fuel in the vicinity of the inlet of the suction port 26b on the end face of the cylinder 26 is less affected by the swirling flow due to the rotation of the motor, and becomes a relatively gentle flow.
Furthermore, the vapor in the fuel generated by the reciprocating motion of the piston 25 is difficult to be sucked into the suction port 26b due to the presence of the partition wall 28b of the bush 28.

Without the partition wall 28b of the bush 28, the swirling flow formed substantially parallel to the end face of the cylinder 26 is in a direction perpendicular to the suction port 26b, so that the fuel sucked into the suction port 26b is a swirling flow. The flow direction is suddenly bent at a right angle from the flow and sucked into the suction port, resulting in an increase in pressure loss at the inlet of the suction port.
According to the first embodiment, the presence of the partition wall 28b of the bush 28 reduces the pressure loss in the fuel when sucked into the suction port 26b, and the amount of vapor is reduced, so the fuel to the pressure increasing chamber is reduced. Vaporization in the inside can be suppressed, and a decrease in pump suction efficiency can be suppressed. Thereby, the pump discharge amount is stabilized.

FIG. 7 shows the pump discharge flow rate characteristic in the temperature raising process of the intake fuel temperature, and shows the ratio of the discharge flow rate at each fuel temperature to the pump discharge flow rate at 20 ° C. as an example.
Under an environment at about atmospheric pressure, the fuel begins to boil and vaporize from around 40 ° C., and as the fuel temperature rises, the amount of vapor generated by the vaporization of the fuel increases in the fuel sucked by the pump. Since the piston pump is a positive displacement pump, the discharge flow rate decreases as the amount of vapor sucked together with the fuel increases.
According to the present invention, as in the first embodiment described above, by suppressing the inflow of vapor to the suction port, it is possible to reduce the decrease in pump discharge flow rate accompanying the increase in fuel temperature compared to the conventional device. .

  Further, since the bush 28 is formed by injection molding of a resin material, the degree of freedom of shape is increased, and the formation of a partition wall 28b in a narrow gap between the piston 25 and the suction port 26b, or formation of a complicated partition shape. Can be manufactured at a low cost.

  As described above, according to the first embodiment, in the fuel supply device in which the pump unit 20 is driven by the motor unit 10 and the fuel sucked by the pump unit 20 is pressurized and discharged, the pump unit 20 includes the suction nipple 23. And a housing 21 having a discharge nipple 24, a cylinder 26 accommodated in the housing and provided with a plurality of pistons 25, and an inclined plate 12 provided on the shaft 11 of the motor unit 10 to reciprocate the plurality of pistons. A plurality of intake ports 26b, which are provided so as to penetrate the cylinder in the axial direction corresponding to each piston, serve as a fuel passage for guiding fuel to the pressure increasing chamber, and both ends are fitted and held in the cylinder and the motor portion, A substantially cylindrical bush 28 for guiding the fuel sucked from the nipple to a plurality of suction ports is provided, and the piston 25 and the suction port 26b include Since they are arranged in different partitioned spaces 28c, the fuel suction pressure loss is reduced, the vapor suction suppression is suppressed, the vapor stays in the pump is prevented, the pump discharge amount is stabilized, and the control fuel pressure is simplified. Can be stabilized.

Embodiment 2. FIG.
8 and 9 are a top view and a C-C cross-sectional view showing the bush according to the second embodiment of the present invention together with the cylinder. As shown in FIGS. 8 and 9, the bush 28 in the second embodiment has a partition wall 28d formed so as to surround the inlet of the suction port 26b in a cylindrical shape.

  According to the second embodiment, as in the first embodiment, the fuel in the vicinity of the suction port 26b is not easily affected by the swirling flow, and vapor generated by the reciprocating motion of the piston 25 is sucked into the suction port 26b. Can be suppressed.

Embodiment 3 FIG.
10 and 11 are a top view and a DD sectional view showing the bush according to the third embodiment of the present invention together with the cylinder, and FIG. 12 is a sectional view showing a positional relationship between the bush and the suction nipple in the third embodiment.
The bush 28 according to the third embodiment is provided with a partition 28e surrounding the outer periphery of the piston 25 and a plurality of suction ports 26b, and a fuel passage 28f formed in a concave shape.
Further, one end of the fuel passage 28f is opened at a position substantially opposite to the suction nipple 23 formed in the housing 21, as shown in FIG.

According to the third embodiment, as in the first embodiment, the fuel in the vicinity of the suction port 26b is less susceptible to the swirling flow, and the piston 25 is inserted into the hole 28g formed in the partition wall 28e of the bush 28. Since it is inserted, it can suppress that the vapor | steam which generate | occur | produces by piston reciprocation is attracted | sucked to the suction port 26b.
Further, by opening the fuel passage 28f at a position facing the suction nipple 23, the inflow resistance from the suction nipple 23 to the suction port 26b is reduced.

Embodiment 4 FIG.
13 and 14 are a top view and a EE cross-sectional view showing the bush according to the fourth embodiment of the present invention together with the cylinder, and FIG. 15 is a cross-sectional view showing the positions of the bush and the suction nipple in the fourth embodiment.
In the fourth embodiment, as shown in FIGS. 13 and 14, the bush 28 is provided with a partition wall 28e surrounding the outer periphery of the piston 25, and a tunnel-like fuel passage 28h connected to the plurality of intake ports 26b is provided in the cylinder of the bush 28. Configure on the end face side.
Further, the lowermost end portion of the fuel passage 28h is disposed on the ground side in the pump mounting direction.

According to the fourth embodiment, the fuel flowing from the suction nipple 23 and flowing toward the suction port 26b flows in the tunnel-shaped fuel passage 28h formed by the cylinder end surface and the bush 28, and flows into the suction port 26b. Is more difficult to be affected by the swirling flow.
Further, since the opening portions at both ends of the fuel passage 28h are configured upward, the vapor generated in the tunnel-like fuel passage 28h is lifted upward by buoyancy even when exposed to an environment such as high-temperature dead soak immediately after the engine is stopped. Therefore, it is possible to prevent the vapor from being sucked into the pump when the engine is restarted.
Further, by opening the tunnel-shaped fuel passage 28h at a position facing the suction nipple 23, the inflow resistance from the suction nipple 23 to the suction port 26b is reduced.

DESCRIPTION OF SYMBOLS 1 Fuel tank 2 Fuel supply apparatus 3 Pressure adjustment apparatus 4 Fuel injection apparatus 5 Control unit 10 Motor part 11 Shaft 12 Inclination plate 13 Partition body, 13a Flange 20 Pump part 21 Housing 22 Screw 23 Intake nipple 24 Discharge nipple 25 Piston 26 Cylinder, 26a piston bore, 26b intake port, 26c stepped portion 27 spring 28 bush, 28a opening, 28b partition wall, 2 8d septum, 28e septum, 28f fuel passage, 28 g hole, 28h fuel passage 29 suction valve 30 discharge valve

Claims (10)

In the fuel supply device that drives the pump unit by the motor unit and pressurizes and discharges the fuel sucked by the pump unit,
The pump unit is provided on a housing having a suction nipple and a discharge nipple, a cylinder accommodated in the housing and provided with a plurality of pistons, and a shaft of the motor unit, and reciprocally moves the plurality of pistons. An inclined plate, a plurality of intake ports provided in the axial direction through the cylinder corresponding to the piston, and serving as a fuel passage for guiding the fuel to the pressure increasing chamber, and both ends of the cylinder and the motor portion A substantially cylindrical bush that is fitted and held and guides fuel sucked from the suction nipple to the plurality of suction ports, and the piston and the suction port are arranged in different spaces that are partitioned from each other . The fuel supply apparatus characterized by the above-mentioned. The fuel supply device according to claim 1, wherein the space is formed by a partition wall provided in the bush. The fuel supply device according to claim 2, wherein the partition wall is formed between the suction port and the piston.   3. The fuel supply apparatus according to claim 2, wherein the partition wall is formed so as to surround the inlet portions of the plurality of suction ports in a cylindrical shape. The partition wall is formed to surround the piston in a cylindrical shape.
The fuel supply apparatus as described.   The fuel supply device according to any one of claims 2 to 5, wherein the partition wall forms a fuel passage for guiding the fuel sucked from the suction nipple to the plurality of suction ports.   The fuel supply device according to claim 6, wherein the fuel passage formed by the partition wall is formed in a concave shape that connects the plurality of suction ports.   The fuel supply apparatus according to claim 6, wherein the fuel passage formed by the partition wall is formed in a tunnel shape connecting the plurality of suction ports on the end face side of the cylinder.   The fuel supply device according to claim 7 or 8, wherein one end of the fuel passage formed by the partition wall is opened at a position facing the housing inner surface side end portion of the suction nipple.   The fuel supply device according to any one of claims 1 to 9, wherein the bush is made of a molded body of a resin material.

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