JP3879952B2 - Fuel supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel supply apparatus, and more particularly to a fuel supply apparatus that increases a fuel discharge amount per predetermined time.
[0002]
[Prior art]
Conventionally, as a high-pressure fuel pump that sucks fuel into a fuel pressurizing chamber when the plunger is lowered when the solenoid valve is opened, and pressurizes the fuel when the plunger is raised when the solenoid valve is closed, Japanese Patent Laid-Open No. Hei 8- What is disclosed in Japanese Patent No. 14140 is known. In such a high-pressure fuel pump, as shown in FIG. 7, when the plunger 101 descends downward in FIG. 7 as the electromagnetic valve 110 is opened, the fuel introduction chamber 103 and the valve member of the electromagnetic valve 110 are discharged from the fuel intake passage 102. Low-pressure fuel is sucked into the fuel pressurizing chamber 104 through an opening between the valve 111 and the valve seat 112.
[0003]
However, if the number of cams for reciprocating the plunger 101 is increased to increase the fuel discharge amount of the high-pressure fuel pump 100 per predetermined time and the reciprocating speed of the plunger 101 is increased, the amount per one intake stroke is increased. The fuel intake time is shortened. Since the high-pressure fuel pump 100 has only one suction path for sucking fuel into the fuel pressurizing chamber 104 from the opening between the valve member 111 and the valve seat 112 when the solenoid valve 110 is opened, the fuel suction time is shortened. Doing so may cause inhalation failure and prevent the necessary amount of fuel from being inhaled. In order to avoid poor suction, it is conceivable to increase the lift amount of the valve member of the solenoid valve or increase the seat diameter of the valve member of the solenoid valve to increase the opening area. There is a problem that it is necessary to significantly change the valve, and the solenoid valve becomes large and the manufacturing cost increases. Furthermore, there is a problem that the responsiveness of the solenoid valve is reduced with the increase in size of the solenoid valve.
[0004]
Thus, in order to avoid fuel intake failure due to shortening of the fuel intake time, a high-pressure fuel pump 120 as shown in FIG. 8 can be considered. When the plunger 101 descends while the solenoid valve 110 is opened, low pressure fuel is sucked into the fuel pressurizing chamber 104 from the fuel suction passage 121 through the fuel introduction chamber 103, the valve member 111 and the valve seat 112. In addition, when the plunger 101 is lowered to the position shown in FIG. 8, the low pressure fuel is sucked directly into the fuel pressurizing chamber 104 from the fuel suction passage 122. As a result, the fuel intake path becomes two paths, so that it is desirable to prevent a decrease in the fuel intake amount per one intake stroke and increase the fuel discharge amount per predetermined time even if the fuel intake time is shortened. It is.
[0005]
[Problems to be solved by the invention]
However, if the outer wall of the plunger 101 does not close the fuel suction passage 122 as the plunger 101 moves up, the pressurized pressure feeding stroke of the fuel is not started. Further, since the fuel suction passage 122 is closed by the outer wall of the plunger 101 in the pressurizing and pressure feeding stroke, the plunger 101 further rises after closing the fuel suction passage 122 until the seal length for the fuel suction passage 122 is secured. Insufficient fuel pressure. Therefore, there is a problem that the fuel discharge amount with respect to the volume of the fuel pressurizing chamber 104 when the plunger 101 reaches the bottom dead center, that is, the discharge efficiency is lowered.
[0006]
An object of the present invention is to provide a fuel supply device that can increase the amount of fuel discharged per predetermined time without increasing the size with a simple structure.
[0007]
[Means for Solving the Problems]
According to the fuel supply device of the first aspect of the present invention, in the fuel intake stroke, the first intake path for sucking the low-pressure fuel from the fuel introduction chamber into the fuel pressurizing chamber through the opening of the electromagnetic valve, and the check valve through an opening low pressure fuel in the fuel suction passage have a second suction passage for sucking the fuel pressurizing chamber, the low pressure fuel that has been assembled from the fuel tank is sucked by the low-pressure pump to the fuel intake passage, The first suction path and the second suction path branch from each other and communicate with the fuel pressurizing chamber independently . Since there are two fuel intake paths to the fuel pressurization chamber, increasing the reciprocating speed of the plunger due to an increase in the number of cam ridges, etc. prevents an increase in manufacturing cost without increasing the overall size of the device In addition, it is possible to secure the fuel intake amount necessary for one intake stroke with a simple configuration.
[0008]
Further, when the plunger rises and the solenoid valve closes and the fuel in the fuel pressurizing chamber is pressurized, the check valve provided in the fuel intake passage is closed. The process starts quickly. Thereby, the fuel discharge amount per predetermined time can be increased.
According to the fuel supply device of the second aspect of the present invention, the fuel introduction chamber is provided in contact with the electromagnetic valve, and the fuel intake passage communicates with the fuel introduction chamber. That is, since the solenoid portion of the solenoid valve is cooled by the relatively low temperature intake fuel flowing in the fuel introduction chamber toward the fuel suction passage, it is possible to prevent malfunction of the solenoid valve due to temperature rise.
[0009]
According to the fuel supply device of the third aspect of the present invention, since the fuel intake passage is opened in the non-sliding portion with the plunger of the cylinder portion, the fuel intake passage is not closed regardless of the movement position of the plunger. Accordingly, a sufficient amount of fuel can be sucked from the fuel suction passage as the plunger moves down.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a high-pressure fuel pump as a fuel supply device according to a first embodiment of the present invention. The high-pressure fuel pump 1 sucks low-pressure fuel pumped from a fuel tank (not shown) by a low-pressure pump (not shown), and supplies the high-pressure fuel pressurized by the high-pressure fuel pump 1 to a distribution pipe (not shown). As many fuel injectors as the number of cylinders are attached to the distribution pipe.
[0011]
A cylinder 12 as a cylinder portion is fixed in the housing 11 of the high-pressure fuel pump 1. The small-diameter portion 12a of the cylinder 12 slides with the plunger 13, and the small-diameter portion 12a supports the plunger 13 so as to be reciprocally movable. The plunger 13 is urged downward in FIG. 1 by a spring 14 and is reciprocated by, for example, four cams (not shown) located in the lower part of FIG.
[0012]
A fuel pressurizing chamber 15 is formed at the end of the plunger 13 by the inner wall of the cylinder 12. The low pressure fuel sucked into the fuel pressurizing chamber 15 by the lowering of the plunger 13 is pressurized by the raising of the plunger 13.
The solenoid valve 20 is disposed above the housing 11, and an annular fuel chamber 25 as a fuel introduction chamber is formed between the solenoid valve 20 and the housing 11. When the energization of the solenoid portion 23 is turned off, the valve member 21 is biased downward in FIG. 1 by the spring 22 and the electromagnetic valve 20 is opened. At this time, the annular fuel chamber 25 and the fuel pressurizing chamber 15 communicate with each other. A path through which low-pressure fuel is sucked into the fuel pressurizing chamber 15 from the annular fuel chamber 25 through the opening of the solenoid valve 20 when the solenoid valve 20 is opened constitutes a first suction path. When energization of the solenoid portion 23 is turned on, the valve member 21 is attracted upward and seated on the valve seat 24 against the urging force of the spring 22. Then, the communication between the annular fuel chamber 25 and the fuel pressurizing chamber 15 is blocked.
[0013]
The fuel intake passage 30 is branched into a fuel intake passage 31 and a fuel intake passage 32. The fuel intake passage 31 communicates with the annular fuel chamber 25. The fuel intake passage 32 opens to a large diameter portion 12b as a non-sliding portion of the cylinder 12 and communicates with the fuel pressurization chamber 15 to prevent backflow of fuel from the fuel pressurization chamber 15 to the fuel intake passage 32. A check valve 40 is disposed in the fuel intake passage 32. A path through which the low-pressure fuel in the fuel suction passage 32 is sucked into the fuel pressurizing chamber 15 through the opening of the check valve 40 constitutes a second suction path. Since the large diameter portion 12b of the cylinder 12 has a larger diameter than the small diameter portion 12a, it does not slide with the plunger 13. Therefore, even if the ascending side end surface of the plunger 13 moves upward in FIG. 1 from the fuel intake passage 32, the fuel intake passage 32 is not blocked by the plunger 13.
[0014]
The fuel discharge passage 33 communicates with the fuel pressurizing chamber 15, and a delivery valve 41 is disposed in the fuel discharge passage 33. The delivery valve 41 opens when the fuel pressure in the fuel pressurizing chamber 15 rises above a predetermined pressure, and high-pressure fuel is supplied from the fuel discharge passage 33 to the distribution pipe.
The fuel discharge passage 34 communicates with the annular fuel chamber 25, and a pressure regulator 42 is disposed in the fuel discharge passage 34. The pressure regulator 42 opens when the pressure of the fuel introduced into the annular fuel chamber 25 from the fuel intake passage 31 exceeds a predetermined pressure, and returns the surplus fuel to a fuel tank (not shown), so that the fuel pressure in the annular fuel chamber 25 is required. It has a function of damaging pressure.
[0015]
Next, the operation of the high pressure fuel pump 1 will be described.
(1) While energization to the suction stroke solenoid unit 23 is turned off, the valve member 21 is separated from the valve seat 24 and the solenoid valve 20 is opened. When the plunger 13 is lowered toward the bottom dead center in this state, the volume of the fuel pressurizing chamber 15 is increased. (1) A path from the annular fuel chamber 25 through the opening of the valve member 21 and the valve seat 24; (2) Low-pressure fuel is sucked into the fuel pressurizing chamber 15 through two paths including a path passing through the fuel suction passage 32. In the intake stroke, the check valve 40 is opened.
[0016]
(2) After the pressure / pressure feed stroke plunger 13 reaches the bottom dead center, when the plunger 13 reaches the position corresponding to the desired fuel discharge amount in the stroke rising toward the top dead center, Turn on the power. When the valve member 21 is lifted against the urging force of the spring 23 by the magnetic force generated by energization of the solenoid 23 and seated on the valve seat 24 and the solenoid valve 20 is closed, the annular fuel chamber 25 and the fuel pressurizing chamber are closed. Communication with 15 is cut off. When the plunger 13 is further raised, the check valve 32 is closed and the fuel in the fuel pressurizing chamber 15 is pressurized as the plunger 13 is raised. When the fuel pressure in the fuel pressurizing chamber 15 exceeds a predetermined pressure, the delivery valve 41 is opened, high-pressure fuel is discharged from the fuel discharge passage 33, and is pumped to the distribution pipe.
[0017]
In the first embodiment, when the electromagnetic valve 20 is opened, the low pressure fuel is sucked from the annular fuel chamber 25 into the fuel pressurizing chamber 15 through the opening of the valve member 21 and the valve seat 24 of the electromagnetic valve 20. In addition to the suction path, a second suction path for directly sucking low-pressure fuel in the fuel suction passage 32 through the opening of the check valve 40 into the fuel pressurizing chamber 15 is provided. Therefore, even if the number of cams is increased to increase the reciprocating speed of the plunger 13 in order to increase the fuel discharge amount per predetermined time, the necessary fuel amount can be sucked in one suction stroke. In addition, since the fuel discharge amount can be increased with a simple configuration in which the fuel suction passage 32 communicating with the fuel pressurizing chamber 15 is added and the check valve 40 is provided in the fuel suction passage 32, the size of the high-pressure fuel pump can be increased. It is possible to suppress an increase in manufacturing cost without being changed.
[0018]
(Second embodiment)
A second embodiment of the present invention is shown in FIG. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals.
The fuel intake passage 50 communicates with the annular fuel chamber 25. The fuel suction passage 51 communicates with the annular fuel chamber 25 on the substantially opposite side of the communication portion of the fuel suction passage 50 with the annular fuel chamber 25, and communicates the annular fuel chamber 25 with the fuel pressurization chamber 15. . The check valve 40 is provided in the fuel intake passage 51. A path through which the low-pressure fuel in the fuel suction passage 51 is sucked into the fuel pressurizing chamber 15 through the opening of the check valve 40 constitutes a second suction path.
[0019]
In the second embodiment, the fuel passing through the annular fuel chamber 25 passes through the openings of the valve member 21 and the valve seat 24 of the electromagnetic valve 20 and is sucked into the fuel pressurizing chamber 15 and fuel from the fuel suction passage 51. The fuel sucked into the pressurizing chamber 15 and the fuel discharged to the outside of the pump through the fuel discharge passage 33, that is, all the fuel supplied to the pump. The large amount of fuel is supplied to the fuel intake passage 51 after contacting the electromagnetic valve 20. Thereby, since the solenoid part 23 of the solenoid valve 20 is cooled by fuel, the malfunction of the solenoid valve 20 accompanying a temperature rise can be prevented.
[0020]
(Third embodiment)
A third embodiment of the present invention is shown in FIG. Components that are substantially the same as those of the second embodiment are denoted by the same reference numerals.
In the second embodiment, the pressure regulator 42 is directly attached to the housing 11 of the high-pressure fuel pump 2, but in the third embodiment, the pressure regulator 42 is attached to the fuel pipe connected to the high-pressure fuel pump 3. Thereby, the exclusive space around the high-pressure fuel pump 3 can be reduced.
[0021]
(Fourth embodiment)
A fourth embodiment of the present invention is shown in FIGS. Components that are substantially the same as those in the first embodiment are denoted by the same reference numerals. There are four cams 100 for driving the high-pressure fuel pump 4.
As shown in FIG. 4, the fuel inlet 50a, the check valve 40, the delivery valve 41, and the pressure regulator 42 are formed in the housing 11 on the cross section of the high-pressure fuel pump 4 including the virtual straight line 110 shown in FIGS. Or attached. Further, the low pressure side fuel inlet 50a and the pressure regulator 42, and the high pressure side of the check valve 40 and the delivery valve 41 are opposed to each other. The fuel inlet 50a and the check valve 40, and the delivery valve 41 and the pressure regulator 42 are formed or attached in parallel. Accordingly, since the fuel pipe can be attached in the same direction, the fuel pipe can be easily attached. Further, since the amount of housing around the fuel inlet 50a and each valve is reduced, the size of the high-pressure fuel pump 4 can be reduced.
[0022]
The virtual extension region of the mounting seat surface of the fuel pipe connected to the fuel inlet 50a to the housing 11 and the mounting seat surface of the check valve 40, the delivery valve 41 and the pressure regulator 42 to the housing 11 includes the plunger 13 and the cylinder. 12 is located radially outside the sliding portion. Therefore, the axial force when screwing the fuel pipe or each valve to the housing 11 is not applied to the sliding portion between the plunger 13 and the cylinder 12. Thereby, since the deformation | transformation of the sliding surface of the cylinder 12 can be prevented, the sliding clearance between the cylinder 12 and the plunger 13 can be maintained at a predetermined amount. Therefore, it is possible to prevent the cylinder 12 and the plunger 13 from burning.
[0023]
The fuel suction passage 52 connects the annular fuel chamber 25 and the check valve 40, the fuel suction passage 53 connects the check valve 40 and the delivery valve 41, and the fuel suction passage 54 is the delivery valve 41. Are connected to the fuel pressurizing chamber 15. The fuel suction passages 52, 53, and 54 constitute a second suction path. Since the fuel suction passage 54 also serves as a fuel discharge passage, the number of processing steps for forming the fuel passage is reduced.
[0024]
In the above-described plurality of examples showing the embodiment of the present invention described above, since the fuel pressurizing chamber 15 is provided with two paths for sucking fuel, in order to increase the discharge amount per predetermined time, the plunger 13 Even if the reciprocating speed is increased, the amount of fuel required per one intake stroke can be sucked. Further, by providing the check valve 40 in the fuel intake passage that directly communicates with the fuel pressurizing chamber 15, the fuel pressurizing chamber 15 can be provided by closing the solenoid valve 20 when the plunger 13 rises toward the top dead center. Since the check valve 40 is closed by the fuel pressure and the fuel pressurization chamber 15 is sealed, the pressurization and pressure feed stroke is started immediately after the solenoid valve 20 is closed. Thereby, a large amount of fuel can be discharged per predetermined time without lowering the discharge efficiency.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a high-pressure fuel pump according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a high-pressure fuel pump according to a second embodiment of the present invention.
FIG. 3 is a longitudinal sectional view showing a high-pressure fuel pump according to a third embodiment of the present invention.
FIG. 4 is a cross-sectional view showing a high-pressure fuel pump according to a fourth embodiment of the present invention.
5 is a cross-sectional view taken along line VV in FIG.
6 is a cross-sectional view taken along line VI-VI in FIG.
7 is a longitudinal sectional view showing a high-pressure fuel pump according to Conventional Example 1. FIG.
8 is a longitudinal sectional view showing a high-pressure fuel pump according to Conventional Example 2. FIG.
[Explanation of symbols]
10 High-pressure fuel pump (fuel supply device)
12 cylinder (cylinder part)
13 Plunger 15 Fuel pressurizing chamber 20 Solenoid valve (first suction path)
21 Valve member 24 Valve seat 25 Annular fuel chamber (fuel introduction chamber, first suction path)
32 Fuel intake passage (second intake route)
33 Fuel discharge passage 34 Fuel discharge passage 40 Check valve (second suction passage)
51 Fuel intake passage (second intake passage)
52, 53, 54 Fuel intake passage (second intake passage)

Claims (3)

A fuel supply device for supplying high pressure fuel to a fuel injection device of an internal combustion engine,
A cylinder part;
A plunger that is reciprocally supported by the cylinder portion and pressurizes the fuel sucked into the fuel pressurizing chamber;
A fuel introduction chamber capable of introducing low-pressure fuel into the fuel pressurization chamber and an electromagnetic valve that intermittently connects the fuel pressurization chamber;
A fuel suction passage provided with a check valve in a passage communicating with the fuel pressurization chamber, and a low pressure fuel is supplied from the fuel introduction chamber to the fuel pressurization chamber through the opening of the electromagnetic valve in the fuel suction stroke; possess a first suction passage for sucking and a second suction passage for sucking the low pressure fuel in the fuel intake passage through the opening of the check valve to the fuel pressurizing chamber, and
Low pressure fuel pumped from a fuel tank by a low pressure pump is sucked into the fuel suction passage, and the first suction path and the second suction path are branched from each other and communicated independently with the fuel pressurizing chamber. The fuel supply apparatus characterized by the above-mentioned .   2. The fuel supply apparatus according to claim 1, wherein the fuel introduction chamber is provided in contact with the electromagnetic valve, and the fuel intake passage communicates with the fuel introduction chamber.   The fuel supply device according to claim 1 or 2, wherein the fuel intake passage is opened in a non-sliding portion of the cylinder portion with respect to the plunger.

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