JP2009197675A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device capable of enhancing the air exhaust performance from a main fuel passage. <P>SOLUTION: In the fuel injection device comprising main fuel passages 111, 112 for guiding the fuel discharged from a feed pump to an injector via a high-pressure pump, and a return fuel passage 130 for returning a part of the fuel discharged from the feed pump to a fuel tank, a separator 36 is arranged between the feed pump and the high-pressure pump in the main fuel passages. Air and the fuel are separated from each other by applying the turning motion to the fuel with air mixed therein in the separator 36. In this condition, since the specific gravity of the air is smaller than that of the fuel, the air gathers in a vicinity of a center part in the radial direction of spaces 360, 361 in the separator 36. Thus, the return fuel passage 130 is opened in the center part in the radial direction of the spaces 360, 361 in the separator 36. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel injection device that injects fuel into a combustion chamber of an internal combustion engine.

The stock pressure fuel injection system for diesel engines includes a common rail that stores high-pressure fuel, a high-pressure pump that pumps high-pressure fuel to the common rail, a feed pump that supplies fuel from the fuel tank to the high-pressure pump, and high-pressure fuel stored in the common rail. The injector etc. which inject | pour into the combustion chamber of this are provided (for example, refer patent document 1). Furthermore, the fuel injection device disclosed in Patent Document 1 returns a part of the fuel discharged from the feed pump to the fuel tank via a cam chamber formed in the housing.
JP 2006-207499 A

  The fuel injection device has a problem that if air is mixed into the main fuel path that guides the fuel discharged from the feed pump to the injector through the high-pressure pump, the injection accuracy decreases or the durability decreases due to cavitation erosion. appear. When a part of the fuel discharged from the feed pump is returned to the fuel tank as in the fuel injection device disclosed in Patent Document 1, a part of the air is returned to the fuel tank together with the fuel. Although discharged from the main fuel path, most of the air is not discharged from the main fuel path.

  In view of the above points, an object of the present invention is to improve the performance of discharging air from a main fuel path.

  In order to achieve the above object, according to the first aspect of the present invention, a fuel tank (30) for storing fuel, a feed pump (32) for pumping and discharging fuel from the fuel tank (30), and a feed pump ( 32) a high pressure pump (33) for further pressurizing and feeding the fuel discharged from the high pressure pump (33), an injector (2) for injecting the fuel pumped from the high pressure pump (33) into the combustion chamber of the internal combustion engine, and a feed pump (32). ) From the main fuel path (110 to 114), and the feed pump (32) and the high pressure pump ( 33), and a swirling motion is given to the fuel flowing into the internal space (360, 361) to separate the fuel mixed with air into air and fuel. Is collected at the radial center of the space (360, 361) and the fuel is collected on the outer peripheral side of the space (360, 361); and the axial end of the space (360, 361) and the space ( 360, 361), and a return fuel path (130, 132) that opens to the fuel tank (30) and returns part of the fuel that has flowed into the space (360, 361). .

  According to this, air and fuel are separated by giving the swirling motion in the separator (36) to the fuel mixed with air. Since air has a specific gravity smaller than that of fuel, air gathers in the vicinity of the central portion in the radial direction of the space (360, 361) in the separator (36). Accordingly, a large amount of air is discharged out of the main fuel path (110 to 114) through the return fuel path (130, 132) opened at the radial center of the space (360, 361) in the separator (36). Thus, the performance of discharging air from the main fuel path (110 to 114) is improved.

  According to a second aspect of the present invention, in the fuel injection device according to the first aspect, the space (360, 361) is separated from the cylindrical space (360) and the cylindrical space (360). A main fuel path (111) having a conical space (361) with a reduced diameter and extending from the feed pump (32) opens into the cylindrical space (360) and reaches the high pressure pump (33). The path (112) opens into a conical space (361), and the return fuel path (130, 132) is an axial end of the cylindrical space (360) and the diameter of the cylindrical space (360). It is characterized by opening in the center of the direction.

  According to this, in the conical space (361), the pressure increases as the distance from the cylindrical space (360) increases. And since air is difficult to flow to the part where the pressure is high, while air is easy to flow to the part where the pressure is low, that is, the cylindrical space (360) side, at the axial end of the cylindrical space (360). Further, more air is discharged out of the main fuel path (110 to 114) via the return fuel path (130, 132) opened at the radial center of the cylindrical space (360), and the main fuel path ( The air discharge performance from 110 to 114) is further improved.

  According to a fifth aspect of the present invention, in the fuel injection device according to any one of the first to fourth aspects, the feed pump (32) and the high pressure pump (33) in the main fuel path (110 to 114). A pressure regulation fuel path (140) branched from between and connected to the upstream side of the feed pump (32) and a pressure regulation fuel path (140) are arranged according to the fuel pressure of the main fuel path (110 to 114). And a pressure regulating valve (35) for adjusting the fuel pressure in the main fuel path (110 to 114) by controlling the passage area of the pressure regulating fuel path (140), and the separator (36) includes a pressure regulating fuel path ( 140) is arranged on the upstream side of the branch portion.

  According to this, since the flow rate of the fuel passing through the separator (36) is larger than when the separator (36) is arranged downstream of the branching portion of the pressure regulating fuel path (140), the return fuel path More air is discharged to the outside of the main fuel path (110 to 114) via (130), and the discharge performance of air from the main fuel path (110 to 114) is further improved.

  According to an eighth aspect of the present invention, in the fuel injection device according to the sixth or seventh aspect, the high pressure pump (33) and the feed pump (32) are accommodated in a common main body housing (37) to form an assembly. The fuel filter (31) is disposed outside the main body housing (37), and the separator (36) is incorporated in the fuel filter (31).

  According to this, it is easier to secure the mounting space for the separator (36) than when the separator (36) is incorporated in the main body housing (37) in which the high-pressure pump (33) and the feed pump (32) are accommodated. .

  In addition, the code | symbol in the bracket | parenthesis of each means described in a claim and this column shows the correspondence with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
A first embodiment of the present invention will be described. FIG. 1 is an overall configuration diagram of a fuel injection device according to a first embodiment.

  This fuel injection device includes a common rail 1 that stores high-pressure fuel, an injector 2 that injects high-pressure fuel in the common rail 1 into each combustion chamber of a diesel engine for vehicles, and a fuel supply device 3 that supplies high-pressure fuel to the common rail 1. Has been.

  The common rail 1 is a livestock pressure unit that holds and stores the high-pressure fuel supplied from the fuel supply device 3 at a target rail pressure. Note that the target rail pressure is determined by a control device (hereinafter referred to as an ECU) (not shown) based on the operation state of the diesel engine such as an accelerator opening signal and an engine speed signal, for example.

  Further, a pressure limiter 1 a is attached to the common rail 1 to open the valve when the fuel pressure in the common rail 1 exceeds a predetermined upper limit value and to release the fuel pressure in the common rail 1. The fuel that has flowed out of the pressure limiter 1 a is returned to the fuel tank 30 of the fuel supply device 3 through the high-pressure system return fuel path 100.

  The injector 2 is fuel injection means for injecting high-pressure fuel into the combustion chamber of a diesel engine. The injector 2 is supplied with high-pressure fuel from the common rail 1 via the main fuel path 110, and surplus fuel that is not injected among the fuel supplied from the common rail 1 is returned to the fuel tank 30 via the high-pressure return fuel path 101. It is. The injector 2 is connected to the ECU, and the fuel injection timing and injection amount are controlled by a control signal from the ECU.

  The fuel supply device 3 includes a fuel tank 30 that stores fuel, a fuel filter 31 that filters the fuel, a feed pump 32 that pumps fuel from the fuel tank 30, and pressurizes the fuel supplied from the feed pump 32 to pump it to the common rail 1. A high pressure pump 33 that adjusts the flow rate of fuel supplied from the feed pump 32 to the high pressure pump 33, a pressure adjustment valve 35 that adjusts the pressure of fuel supplied from the feed pump 32 to the high pressure pump 33, and air The separator 36 is configured to separate air and fuel by giving a swirling motion to the mixed fuel.

  The fuel supply device 3 is an assembly in which a feed pump 32, a high-pressure pump 33, a suction metering valve 34, a pressure regulating valve 35, and a separator 36 are accommodated in a common main body housing. The fuel tank 30 and the fuel filter 31 are disposed outside the main body housing.

  The fuel tank 30 and the feed pump 32 are connected via an intake fuel path 120, and a fuel filter 31 is disposed in the intake fuel path 120.

  The feed pump 32 supplies the fuel pumped up from the fuel tank 30 via the intake fuel path 120 to the high-pressure pump 33. In this embodiment, a trochoid pump, which is an internal gear pump, is employed as the feed pump 32, which is connected to the cam shaft 330 of the high-pressure pump 33, and the rotational driving force is transmitted from the cam shaft 330.

  A separator 36 (described later in detail) is connected to the downstream side of the feed pump 32 via a main fuel path 111. The separator 36 has two outlets, and one outlet is connected to the cam chamber 331 of the high-pressure pump 33 via the return fuel path 130, and this cam chamber 331 is connected to the fuel tank 30 via the return fuel path 131. It is connected. The other outlet of the separator 36 is connected to the intake metering valve 34 via the main fuel path 112.

  The intake metering valve 34 is a linear solenoid type electromagnetic valve configured such that the valve opening can be continuously changed, and the valve opening is controlled by a control signal output from the ECU based on the operating state of the diesel engine. Be controlled.

  The pressure regulating fuel path 140 branched from the main fuel path 111 connecting the feed pump 32 and the separator 36 is connected to the upstream side of the feed pump 32, and the pressure regulating valve 35 is provided in the pressure regulating fuel path 140. Has been placed.

  The pressure regulating valve 35 is configured to include a valve body portion that adjusts the fuel passage opening degree, a spring means that urges the valve body portion to close the valve body portion, and the like, and between the feed pump 32 and the separator 36 by a mechanical mechanism. The pressure of the fuel is controlled to a constant pressure.

  A high pressure pump 33 is connected to the downstream side of the intake metering valve 34 via a main fuel path 113. The high-pressure pump 33 includes a camshaft 330 that is driven and rotated by a diesel engine and a plunger 332 as a pressurizing unit that pressurizes fuel by reciprocating inside the cylinder, as shown in a one-dot chain line in FIG. And so on.

  The cam shaft 330 is connected to a cam 333 that converts the rotational motion of the cam shaft 330 into a linear motion and transmits the linear motion to the plunger 332.

  A pressurizing chamber 334 whose volume changes in accordance with the reciprocating motion of the plunger 332 is formed inside the cylinder. Fuel is supplied to the pressurizing chamber 334 via the main fuel path 113. A suction valve 335 that opens when fuel is sucked into the pressurizing chamber 334 is disposed in the main fuel path 113. The pressurizing chamber 334 is connected to the common rail 1 through the main fuel path 114. A discharge valve 336 that opens when fuel is discharged from the pressurizing chamber 334 is disposed in the main fuel path 114.

  The cam 333 is disposed in a cam chamber 331 formed in the main body housing, and the fuel guided to the cam chamber 331 via the return fuel path 130 described above is in contact with a portion where the cam 333 and the plunger 332 slide. Acts as a lubricant. In the return fuel path 130, an orifice 337 for appropriately setting the flow rate of the fuel supplied to the cam chamber 331 is disposed.

  Next, the separator 36 will be described. 2A is a front view schematically showing the separator 36, and FIG. 2B is a left side view of FIG. 2A.

  As shown in FIG. 2, the separator 36 includes a columnar first space 360 and a conical second space 361. The first space 360 and the second space 361 are arranged coaxially. In addition, the first space 360 and the second space 361 are arranged adjacent to each other. At this time, the second space 361 is arranged so that the diameter decreases as the distance from the first space 360 increases. Yes.

  The main fuel path 111 extending from the feed pump 32 (see FIG. 1) opens at a position on the outer peripheral side of the first space 360 and near the end portion on the side opposite to the second space. The direction of the portion that opens to the first space 360 in the main fuel path 111 is shifted in the radial direction from the axis of the first space 360, thereby turning the fuel flowing from the main fuel path 111 into the first space 360. Is supposed to give.

  The main fuel path 112 leading to the intake metering valve 34 (see FIG. 1) is open on the outer peripheral side of the second space 361 and near the end on the side opposite to the first space. The direction of the portion that opens to the second space 361 in the main fuel path 112 is shifted in the radial direction from the axis of the second space 361.

  The return fuel path 130 reaching the cam chamber 331 (see FIG. 1) of the high-pressure pump 33 opens at the end of the first space 360 on the side opposite to the second space and in the radial center of the first space 360. .

  FIG. 3 is a cross-sectional view showing a specific configuration of the separator 36. As shown in FIG. 3, the separator 36 is configured by inserting a plug 362 into a cylindrical hole 371 formed in the main body housing 37. The plug 362 is press-fitted or screwed into the main body housing 37. Incidentally, the main body housing 37 also accommodates the feed pump 32, the high-pressure pump 33, the suction metering valve 34, and the pressure regulating valve 35 shown in FIG.

  A portion of the cylindrical hole 371 where the plug 362 does not enter is a first space 360. The second space 361 is formed in the plug 362. The plug 362 is formed with a communication hole 363 that allows communication between the second space 361 and the outer peripheral portion of the plug 362. The second space 361 is connected to the intake metering valve 34 (see FIG. 1) via the communication hole 363. Is connected to the main fuel path 112. The communication hole 363 forms a part of the main fuel path 112 leading to the intake metering valve 34.

  Next, the operation of the apparatus of the present embodiment configured as described above will be described. First, the camshaft 330 of the high-pressure pump 33 rotates with the operation of the diesel engine. As described above, since the feed pump 32 is connected to the cam shaft 330, the rotational driving force is transmitted from the cam shaft 330 to the feed pump 32.

  The feed pump 32 is driven by this driving force, and the feed pump 32 pumps fuel from the fuel tank 30 through the intake fuel path 120. The fuel pumped from the feed pump 32 flows into the intake metering valve 34 through the main fuel paths 111 and 112.

  Since the valve opening degree of the intake metering valve 34 is controlled by a control signal output from the ECU, fuel having a flow rate sufficient for the operation of the diesel engine flows into the high-pressure pump 33 via the main fuel path 113. To do.

  Further, when the cam 333 rotates together with the cam shaft 330, the plunger 332 of the high-pressure pump 33 reciprocates. When the plunger 332 moves inside the cylinder toward the camshaft 330 by this reciprocating motion, the volume of the pressurizing chamber 334 increases and the pressure in the pressurizing chamber 334 decreases. As a result, the suction valve 335 is opened, and the fuel downstream of the suction metering valve 34 is sucked into the pressurizing chamber 334.

  Further, when the plunger 332 moves inside the cylinder to the opposite cam shaft side, the volume of the pressurizing chamber 334 is reduced and the fuel sucked into the pressurizing chamber 334 is pressurized. When the pressure of the pressurized fuel exceeds the valve opening pressure of the discharge valve 336, the discharge valve 336 is opened, and the fuel in the pressure chamber 334 is pumped to the common rail 1 through the main fuel path 114.

  As a result, the high-pressure fuel is stored in the common rail 1. The high-pressure fuel stored in the common rail 1 is injected into each combustion chamber of the diesel engine from an injector 2 driven by a control signal from the ECU.

  Here, when air is mixed into the fuel from the fuel tank 30 or the like, the air is discharged out of the main fuel paths 110 to 114 as follows.

  That is, when the fuel discharged from the feed pump 32 flows into the first space 360 of the separator 36, a swirling motion is given to separate the air and the fuel. At this time, fuel having a specific gravity greater than that of air gathers on the outer peripheral side of the space in the separator 36, and air having a specific gravity smaller than that of the fuel gathers in the vicinity of the central portion in the radial direction of the space in the separator 36. Further, in the second space 361, the pressure increases as the distance from the first space 360 increases, so that air gathers on the first space 360 side where the pressure is low. Therefore, air tends to gather near the radial center of the first space 360.

  Then, fuel with a high air mixing rate collected near the radial center of the first space 360 is returned to the fuel tank 30 via the return fuel paths 130 and 131, and a large amount of air is outside the main fuel paths 110 to 114. To be discharged.

  On the other hand, the fuel having a low air mixing rate that has flowed to the second space 361 side is supplied to the intake metering valve 34 via the main fuel path 112. Thus, since the fuel with a low air mixing rate is supplied to the main fuel paths 110 to 114, the deterioration of the injection accuracy and the durability due to cavitation erosion are prevented or suppressed.

(Modification of the first embodiment)
In the embodiment described above, the separator 36 may be arranged upstream of the branch portion of the pressure regulating fuel path 140 as in the first modification shown in FIG. According to this, since the flow rate of the fuel passing through the separator 36 is larger than when the separator 36 is arranged on the downstream side of the branch portion of the pressure regulating fuel path 140, the fuel flows through the return fuel paths 130 and 131. More air is discharged out of the main fuel paths 110 to 114, and the performance of discharging air from the main fuel paths 110 to 114 is further improved.

  In the second modified example shown in FIG. 5, the pipe 364 that forms a part of the return fuel path 130 is press-fitted into the main body housing 37, and the opening end of the pipe 364 is positioned in the first space 360. More specifically, the opening end portion of the pipe 364 is positioned at a portion where air is easily collected in the first space 360. According to this, more air is discharged out of the main fuel paths 110 to 114 via the return fuel paths 130 and 131, and the performance of discharging air from the main fuel paths 110 to 114 is further improved.

  In the third modification shown in FIG. 6, the filter 365 is provided between the opening of the main fuel path 111 extending from the feed pump 32 (see FIG. 1) and the communication hole 363 of the plug 362 in the separator 36. Is arranged. According to this, since the movement of air to the communication hole 363 side is blocked by the filter 365, the air mixing rate of the fuel supplied to the intake metering valve 34 (see FIG. 1) is further reduced.

  In the fourth modification shown in FIG. 7, the first space 360 and the second space 361 are formed in the plug 362. The plug 362 has a communication hole 366 that communicates the first space 360 and the outer periphery of the plug 362, and the first space 360 is connected to the main fuel path 111 extending from the feed pump 32 via the communication hole 366. It is connected. The communication hole 366 forms part of the main fuel path 111 extending from the feed pump 32 (see FIG. 1). In this case, since the direction of the main fuel path 111 extending from the feed pump 32 can be orthogonal to the axis of the hole 371 of the main body housing 37, a burr is generated at a portion of the main fuel path 111 that opens to the hole 371. Hateful.

(Second Embodiment)
A second embodiment of the present invention will be described. FIG. 8 is an overall configuration diagram of the fuel injection device according to the second embodiment, and FIG. This embodiment is different from the first embodiment in the configuration of the fuel supply device 3 and the arrangement position of the separator 36.

  As shown in FIG. 8, in the intake fuel path 120, a pre-filter 38 that filters out the fuel sucked from the fuel tank 30 and removes foreign matter, and the air in the fuel path is vented when the vehicle is assembled. For this purpose, a priming pump 39 that pumps fuel from the fuel tank 30 by manual operation and pumps it is disposed. Further, a goose filter 40 is provided on the inlet side of the feed pump 32 in the intake fuel path 120 to remove foreign matters mixed in the fuel in the fuel path after the prefilter 38.

  A separator 36 is connected to the downstream side of the feed pump 32 via a main fuel path 111. Further, a fuel filter 31 is disposed on the downstream side of the separator 36. The fuel filter 31 is connected to the intake metering valve 34 via the main fuel path 112. The fuel filter 31 is connected to the fuel tank 30 via a return fuel path 132.

  The return fuel path 132 is provided with a relief valve 41 that opens the return fuel path 132 when the fuel pressure in the main fuel path (more specifically, the fuel pressure acting on the fuel filter 31) exceeds a predetermined pressure. ing. When the relief valve 41 is opened, part of the fuel discharged from the feed pump 32 is returned to the fuel tank 30 via the return fuel path 132.

  In the present embodiment, a value that is equal to or higher than the discharge pressure of the feed pump 32 when the engine is started and less than the discharge pressure of the feed pump 32 when the engine is idling is set as a predetermined value at which the relief valve 41 opens. is doing. As a result, the relief valve 41 is always opened after the engine is started, and air is released.

  In addition, since the discharge pressure from the feed pump 32 can be applied to the fuel filter 31, a filter having a finer filtration performance than the pre-filter 38 and the goose filter 40 can be employed for the fuel filter 31. Therefore, the fuel filter 31 can remove small foreign matters, moisture, and the like that cannot be removed by the pre-filter 38 and the goose filter 40.

  Further, a return fuel path 150 connects between the feed pump 32 and the fuel filter 31 and between the priming pump and the feed pump 32. The return fuel path 150 is provided with a return valve 42 that adjusts the fuel flow rate that passes through the return fuel path 150 and returns to the upstream side of the feed pump 32.

  The return valve 42 is configured to include a valve body portion that adjusts the fuel passage opening degree, a spring means that urges the valve body portion to close, and a fuel on the downstream side of the feed pump 32 by a mechanical mechanism. It is a pressure control valve that adjusts so that the pressure becomes a predetermined value. The return valve 42 can prevent the excessive fuel pressure from the feed pump 32 from acting on the fuel filter 31.

  In the main fuel path 112 from the fuel filter 31 to the intake metering valve 34, an orifice 43 for appropriately setting the flow rate of the fuel passing through the fuel filter 31 is disposed.

  Of the main fuel path 112 from the fuel filter 31 to the intake metering valve 34, a pressure regulating fuel path 140 is branched from a portion downstream of the orifice 43 and upstream of the intake metering valve 34. A pressure regulating valve 35 is disposed in the pressure regulating fuel path 140.

  Of the pressure regulation fuel path 140, the return fuel path 130 is branched from between the main fuel path 112 and the pressure regulation valve 35. The return fuel path 130 is connected to the cam chamber 331 of the high-pressure pump 33.

  An excess fuel return path 160 is branched from a main fuel path 113 extending from the intake metering valve 34 to the high-pressure pump 33. The surplus fuel return path 160 is connected to a portion of the intake fuel path 120 downstream of the pre-filter 38 and upstream of the goose filter 40. For example, when the intake metering valve 34 is closed, surplus fuel on the downstream side of the intake metering valve 34 can be returned to the upstream side of the feed pump 32 via the surplus fuel return path 160. The surplus fuel return path 160 is provided with an orifice 44 for appropriately setting the flow rate of the fuel passing through the surplus fuel return path 160.

  The high pressure pump 33 is provided with two plungers 332, a suction valve 335, and two discharge valves 336. Specifically, the two plungers 332 are arranged so as to oppose each other in the radial direction of the cam shaft 331, and the fuel is sucked and pumped alternately.

  A bypass fuel path 170 for sending the fuel pumped up by the priming pump 39 to the downstream side of the feed pump 32 is connected to the intake fuel path 120 downstream of the pre-filter 38 and upstream of the goose filter 40. Yes. In the bypass fuel path 170, a check valve 45 that prevents back flow of fuel is disposed.

  The fuel supply device 3 includes a feed pump 32, a high-pressure pump 33, a suction metering valve 34, a pressure regulating valve 35, a goose filter 40, a return valve 42, and orifices 43 and 44 housed in a common body housing. It has become.

  In the fuel supply device 3, the fuel tank 30, the fuel filter 31, the separator 36, the prefilter 38, the priming pump 39, the relief valve 41, and the check valve 45 are disposed outside the main body housing.

  Further, the separator 36 and the relief valve 41 are incorporated in the fuel filter 31. That is, as shown in FIG. 9, the separator 36 is configured by inserting a plug 362 into a cylindrical hole 311 formed in the housing 310 of the fuel filter 31. The plug 362 is press-fitted or screwed into the filter housing 310.

  In the relief valve 41, a bottomed cylindrical sleeve 410 is inserted into a cylindrical hole 312 formed in the filter housing 310. The sleeve 410 is press-fitted or screwed into the filter housing 310. In the sleeve 410, a valve body 411 that opens and closes the return fuel path 132 and a spring 412 that biases the valve body 411 in the valve closing direction are arranged.

  In the apparatus of the present embodiment, the fuel discharged from the feed pump 32 is given a swirl motion when flowing into the first space 360 of the separator 36, and the air and the fuel are separated. At this time, the fuel tends to gather on the outer peripheral side of the space in the separator 36, and the air tends to gather near the central portion in the radial direction of the first space 360.

  Then, fuel with a high air mixing rate collected near the radial center of the first space 360 is returned to the fuel tank 30 via the return fuel path 132 when the relief valve 41 is opened, and a large amount of air is returned to the main fuel. It is discharged out of the paths 110 to 114.

  On the other hand, the fuel having a low air mixing rate that has flowed toward the second space 361 flows into the chamber containing the filter element in the fuel filter 31 via the main fuel path 112 and is filtered by the filter element. It is supplied to the intake metering valve 34.

  As in the fuel supply device 3 of the present embodiment, when the separator 36 is incorporated in the fuel filter 31, the separator 36 is more than in the case where the separator 36 is incorporated in the main body housing in which the feed pump 32, the high pressure pump 33, and the like are accommodated. It is easy to secure 36 mounting spaces.

  In this embodiment, the fuel filter 31 is disposed on the downstream side of the separator 36. However, the fuel filter 31 is disposed between the feed pump 32 and the separator 36 as in the modification shown in FIG. May be.

(Other embodiments)
In each of the above embodiments, the separator 36 includes the columnar first space 360 and the conical second space 361, but a separator including only the columnar space may be used. Alternatively, a separator having only a conical space may be used.

1 is an overall configuration diagram of a fuel injection device according to a first embodiment of the present invention. (A) is the front view which shows typically the separator 36 of FIG. 1, (b) is a left view of (a). It is sectional drawing which shows the specific structure of the separator 36 of FIG. It is a whole block diagram of the fuel-injection apparatus which shows the 1st modification of 1st Embodiment. It is sectional drawing of the separator 36 which shows the 2nd modification of 1st Embodiment. It is sectional drawing of the separator 36 which shows the 3rd modification of 1st Embodiment. It is sectional drawing of the separator 36 which shows the 4th modification of 1st Embodiment. It is a whole block diagram of the fuel-injection apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the principal part of the fuel filter 31 of FIG. It is a whole block diagram which shows the modification of the fuel-injection apparatus which concerns on 2nd Embodiment.

Explanation of symbols

2 Injector 30 Fuel tank 32 Feed pump 36 Separator 110-114 Main fuel path 130-132 Return fuel path 360 Cylindrical space 361 Conical space

Claims (8)

A fuel tank (30) for storing fuel;
A feed pump (32) for pumping and discharging fuel from the fuel tank (30);
A high-pressure pump (33) for further pressurizing and feeding the fuel discharged from the feed pump (32);
An injector (2) for injecting fuel pumped from the high-pressure pump (33) into a combustion chamber of an internal combustion engine;
A main fuel path (110 to 114) for guiding the fuel discharged from the feed pump (32) to the injector (2) via the high-pressure pump (33);
Among the main fuel paths (110 to 114), the fuel is disposed between the feed pump (32) and the high-pressure pump (33), and swirls the fuel flowing into the internal spaces (360, 361). A separator (36) that separates the fuel mixed with air into air and fuel, collects air at the center in the radial direction of the space (360, 361), and collects fuel at the outer peripheral side of the space (360, 361). )When,
A portion of the fuel that opens at the axial end of the space (360, 361) and at the center in the radial direction of the space (360, 361) flows into the space (360, 361). And a return fuel path (130, 132) for returning to the fuel injection device. The space (360, 361) includes a columnar space (360) and a conical space (361) whose diameter decreases as the distance from the columnar space (360) increases.
The main fuel path (111) extending from the feed pump (32) opens into the cylindrical space (360),
The main fuel path (112) leading to the high pressure pump (33) opens into the conical space (361),
The return fuel path (130, 132) is open at an axial end of the cylindrical space (360) and at a radial center of the cylindrical space (360). Item 4. The fuel injection device according to Item 1. A main body housing (37) for accommodating the high-pressure pump (33);
The high-pressure pump (33) includes a pressurizing unit (332) for pressurizing fuel, a cam shaft (330) driven by the internal combustion engine, and the pressurizing unit (330) as the cam shaft (330) rotates. 332) and a cam (333) for driving,
The body housing (37) is formed with a cam chamber (331) for accommodating the cam (333),
The fuel injection device according to claim 1 or 2, wherein the return fuel path (130) is connected to the fuel tank (30) via the cam chamber (331).   The fuel injection device according to claim 3, wherein the separator (36) is incorporated in the main body housing (37). The pressure regulating fuel path (140) branched from between the feed pump (32) and the high pressure pump (33) in the main fuel path (110 to 114) and connected to the upstream side of the feed pump (32). )When,
The main fuel path (110-114) is disposed in the pressure-regulated fuel path (140), and controls the passage area of the pressure-regulated fuel path (140) according to the fuel pressure of the main fuel path (110-114). And a pressure regulating valve (35) for adjusting the fuel pressure of
The fuel injection device according to any one of claims 1 to 4, wherein the separator (36) is disposed upstream of a branch portion of the pressure-regulating fuel path (140). A fuel filter (31) for filtering fuel;
The fuel filter (31) is disposed between the feed pump (32) and the high pressure pump (33) in the main fuel path (110 to 114),
The fuel injection device according to claim 1 or 2, wherein the return fuel path (132) is connected to the fuel tank (30).   A relief valve (41) disposed in the return fuel path (132) and opening the return fuel path (132) when the fuel pressure in the main fuel path (110 to 114) exceeds a predetermined pressure; The fuel supply device according to claim 6. The high-pressure pump (33) and the feed pump (32) are accommodated in a common body housing (37) to form an assembly,
The fuel filter (31) is disposed outside the main body housing (37),
The fuel injection device according to claim 6 or 7, wherein the separator (36) is incorporated in the fuel filter (31).

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