JP4379389B2 - High pressure fuel supply pump - Google Patents

Description

  The present invention relates to a high-pressure fuel supply system that supplies high-pressure fuel to a fuel injection valve of a direct injection internal combustion engine that directly injects fuel into a combustion chamber of an engine, and a high-pressure fuel supply pump. The present invention relates to a system and a high-pressure fuel supply pump.

  High pressure fuel supply system and high pressure fuel to prevent foreign matter mixed in the fuel from entering and prevent malfunction due to foreign matter biting into the solenoid valve, plunger sliding part or discharge valve in the high pressure fuel supply pump Japanese Patent Application Laid-Open No. 11-229989 discloses that a fuel filter is provided in the fuel suction passage of the supply pump and foreign matter is filtered by the filter.

  In general, JP-A-7-213823 discloses that a filter is attached to a joint portion of a pipe in order to remove solid particles in a fluid.

Japanese Patent Laid-Open No. 11-229989 Japanese Patent Laid-Open No. 7-213823

  However, in the high pressure fuel supply pump disclosed in Japanese Patent Application Laid-Open No. 11-229989, a filter is provided at the suction passage inlet of the casing of the high pressure fuel supply pump, so that the casing structure can be simplified, the filter size can be liberalized and replaced. The problem is that the work is difficult.

  In the filter mechanism provided in the joint part described in Japanese Patent Laid-Open No. 7-213823, there is no contrivance for preventing fluid pulsation in the suction passage of the high pressure fuel supply pump.

  An object of the present invention is to simplify the casing structure of a high-pressure pump, to facilitate the replacement of a filter size and to facilitate replacement, or to further suppress the fuel pulsation in the suction passage of the high-pressure pump while achieving the above object. For either purpose.

  In order to achieve the above object, the present invention provides a filter in a fuel passage of a joint connecting a suction passage inlet of a casing in which a suction passage of a high pressure fuel supply pump is formed and a low pressure fuel supply pipe, or a low pressure. Either a fuel throttle part is provided at the head of the filter attached to the fuel passage of the joint provided in the fuel supply pipe.

  Preferably, a filter is provided in the fuel passage of the joint connecting the suction passage inlet of the casing formed with the suction passage of the high-pressure fuel supply pump and the low-pressure fuel supply pipe, and a fuel throttle portion is provided at the mounting head of the filter. Is.

  According to the present invention configured as described above, when the parts are replaced in the market, the filter is detachable from the casing of the high-pressure fuel supply pump, so that the replacement work is easy and the workability is good. Is obtained.

  Alternatively, fuel pulsation in the intake passage can be reduced by restricting the mounting head.

  Embodiments of a high-pressure fuel supply system and a high-pressure fuel pump in which the present invention is implemented will be described with reference to FIGS.

  The first embodiment of the present invention will be specifically described with reference to FIGS.

  1 is a vertical sectional view of the entire pump, FIGS. 2 to 4 are enlarged views of a fuel filter, and FIG. 5 is a block diagram of a fuel injection system.

  A fuel suction passage 10, a discharge passage 11, and a pressurizing chamber 12 are formed in the casing 1. The fuel intake passage 10 and the discharge passage 11 are provided with an intake valve 5 and a discharge valve 6, respectively, which are held in one direction by springs 5a and 6a, respectively, and serve as check valves that restrict the direction of fuel flow. Yes. The pressurizing chamber 12 is formed by a pump chamber 12 a in which the plunger 2 as a pressurizing member slides, a suction hole 5 b communicating with the suction valve 5, and a discharge hole 6 b communicating with the discharge valve 6.

  A solenoid 200 is held in the pump body 1 in the suction chamber 10a, and an engaging member 201 and a spring 202 are disposed on the solenoid 200. When the solenoid 200 is OFF, the engaging member 201 is biased by a spring 202 in a direction to open the suction valve 5. Since the biasing force of the spring 202 is larger than the biasing force of the suction valve spring 5a, when the solenoid 200 is OFF, the suction valve 5 is in an open state as shown in FIG. The fuel is led from the tank 50 to the fuel inlet of the pump body 1 by the low-pressure pump 51, adjusted to a constant pressure by the pressure regulator 52. After that, the pump body 1 is pressurized and is pumped from the fuel discharge port to the common rail 53. An injector 54, a relief valve 55, and a pressure sensor 56 are attached to the common rail 53. The injectors 54 are mounted in accordance with the number of cylinders of the engine and inject with signals from an engine control unit (ECU) 40. The relief valve 55 opens when the pressure in the common rail 53 exceeds a predetermined value, and prevents damage to the piping system. The fuel pipe of the relief valve 55 is connected to the joint 100.

  A screw portion 110 is threaded on the inner peripheral portion of the suction passage inlet portion 100a of the casing 1. On the other hand, a threaded portion 100 </ b> A is also formed on the outer periphery of the joint 100. The joint 100 is fixed by screwing the threaded portion 100A into the threaded portion 110 of the suction passage inlet portion 100a.

  At this time, the metal washer 111 disposed between the tip of the joint 100 and the mounting bottom surface 112 of the suction passage inlet 100a is sandwiched between the two. As a reaction force, the metal washer 111 applies a load in the thrust direction to the joint 100 to obtain a screw loosening prevention effect.

  At the center of the joint 100, a fuel passage 114 having a minimum passage diameter D1 as a fuel passage is formed on the side where the screw portion 113 for connection to the low-pressure fuel supply pipe is formed. A fuel passage 115 having a larger passage diameter D2 is formed on the threaded portion 100A side.

  The passage diameter D2 is set to a passage diameter necessary for attaching the filter 120. In this embodiment, the passage diameter is set to be approximately equal to the passage diameter D2 of the fuel suction passage 10 formed in the casing portion.

  The passage diameter of the metal washer 112 is set larger than any of these.

  The filter 120 is fixed to the joint 100 by press-fitting the fixing head holder 122 into the inner wall surface of the fuel passage 115 having the passage diameter D2 of the joint 100 so that the metal mesh or resin net 121 is positioned on the low-pressure pipe side. Is done.

  A specific configuration of the filter will be described below in detail with reference to FIGS.

  The fixing head holding body 122 is made of a resin material, and one end periphery of a metal mesh or a resin net 121 is molded on the annular portion 123 by a resin. A metal ring 125 is attached to the annular portion 123 by caulking. The outer periphery of the metal ring 125 is press-fitted into the inner wall surface of the fuel passage 115.

  The inner diameter D3 of the end portion on the metal mesh or resin net 121 side of the annular portion 123 is smaller than the inner diameter D4 of the end portion on the metal washer side 111 side and is formed with an inclination. Accordingly, the inner diameter D3 of the end portion on the metal mesh or resin net 121 side of the annular portion 123 is set smaller than both the passage diameter D2 of the fuel passage 115 and the inner diameter D1 of the inlet side passage 114 of the joint 100.

  A part of the annular part 123 is formed with a pair of legs 124 integrally molded with the annular part 123 in the axial direction. At this part, a part of the metal mesh or the resin net 121 is placed in the resin member. Molded. The peripheral edge of the metal mesh or resin net 121 on the side opposite to the annular portion is molded in a resin disk portion 126.

  A resin holder for the metal mesh or the resin net 121 is formed by the annular portion 123, the pair of leg portions 124, and the disk portion 126.

  On the inner periphery of the annular portion 123, a portion projecting inward is located at a portion corresponding to the leg portion 124. Accordingly, the passage sectional area of the smallest passage D3 is further reduced by the sectional integral of the pair of legs 124.

  In this way, a throttle portion of the fuel passage is formed at the low pressure side fuel passage of the high pressure pump, in the embodiment, the low pressure fuel inlet portion of the casing 1 by the resin holder of the filter 120 attached to the joint 100.

  Thereby, the pulsation of the fuel generated in the low-pressure passage of the high-pressure pump is reduced by the throttle portion.

  The throttle part can be molded into any shape by resin molding, so the throttle part can be easily formed according to the requirements of the high-pressure pump or high-pressure fuel supply system, and at the same time the filter is installed, the throttle part can also be installed. .

  Furthermore, a large space for depositing the purified material can be secured between the fuel passage 115 and the metal mesh of the filter 120 or the outer periphery of the resin net 121.

Foreign matter in gasoline gathers along the flow around the outer periphery of the fixing head holder 122, which is the large-diameter portion of the filter 120, and the accumulation of the purified product proceeds from there. The flow path can be secured over a long period.

  The metal mesh or resin net 121 of the filter 120 is first inserted into the fuel passage of the joint 100 toward the low pressure side (upstream side), and finally the outer periphery of the fixing head holding body 122 is press-fitted into the inner periphery of the passage. Since the filter 120 is mounted, the tip of the filter 120 comes into contact with the passage and the resin is scraped to generate resin debris, or even if metal powder is generated in the press-fitting portion during metal ring press-fitting, resin debris and metal powder Occurs on the upstream side of the filter, so that the resin fragments and metal powder do not flow into the pump.

  The operation will be described below based on the system diagram shown in FIG.

  A lifter 3 provided at the lower end of the plunger 2 is pressed against a cam 7 by a spring 4. The plunger 2 is slidably held by the cylinder 20 and reciprocates by the cam 7 rotated by an engine cam shaft or the like to change the volume in the pressurizing chamber 12.

  A plunger seal 30 is provided at the lower end of the cylinder 20 in the drawing to prevent fuel from flowing out to the cam 7 side.

  When the suction valve 5 is closed during the compression process of the plunger 2, the pressure in the pressurizing chamber 12 rises, whereby the discharge valve 6 is automatically opened and the fuel is pumped to the common rail 53.

  The suction valve 5 automatically opens when the pressure in the pressurizing chamber 12 becomes lower than the fuel inlet, but the valve closing is determined by the operation of the solenoid 200.

  When the solenoid 200 is kept in the ON (energized) state, an electromagnetic force greater than the urging force of the spring 202 is generated, and the engaging member 201 is pulled toward the solenoid 200, so that the engaging member 201 and the suction valve 5 are separated. The In this state, the intake valve 5 is an automatic valve that opens and closes in synchronization with the reciprocating motion of the plunger 2. Therefore, during the compression process, the suction valve 5 is closed, and the fuel corresponding to the volume reduction of the pressurizing chamber 12 pushes the discharge valve 6 and is pumped to the common rail 53.

  On the other hand, when the solenoid 200 is kept OFF (non-energized), the engagement member 201 is engaged with the suction valve 5 by the biasing force of the spring 202, and the suction valve 5 is held in the open state. Accordingly, even during the compression process, the pressure in the pressurizing chamber 12 is maintained at a low pressure that is substantially equal to that of the fuel introduction port, so that the discharge valve 6 cannot be opened, and the volume reduction of the pressurizing chamber 12 is reduced. The fuel is returned to the fuel inlet side through the intake valve 5.

  Further, if the solenoid 200 is turned on during the compression process, the fuel is fed to the common rail 53 from this time. In addition, once the pressure feeding is started, the pressure in the pressurizing chamber 12 is increased. Thereafter, even if the solenoid 200 is turned off, the suction valve 5 is maintained in the closed state, and the suction process is automatically performed in synchronization with the start. Open the valve.

  Therefore, as the plunger 2 reciprocates, the fuel is sucked from the fuel suction passage 10 into the pressurization chamber 12, discharged from the pressurization chamber 12 to the common rail 53, and returned from the pressurization chamber 12 to the fuel suction passage. One process will be repeated.

  A joint 100 for connecting a low-pressure fuel pipe (not shown) extending from the low-pressure pump 51 is provided at the inlet of the fuel intake passage 10 of the casing 1, and a filter is provided at an opening facing the casing 1 side end surface of the joint. Yes. Since the filter 120 can prevent foreign matters mixed in the fuel supplied from the low pressure pump 51 from malfunctioning due to foreign matter biting into the electromagnetic valve, the engagement member 201, and the discharge valve 6 in the high pressure fuel supply pump. It is to prevent. Further, the filter 120 has a substantially cylindrical net, and an edge portion that is partially thickened is formed on the outer periphery of the maximum diameter portion. The edge is pressed into the step and fixed. The inlet portion of the fuel intake passage 10 of the casing 1 has a smaller diameter than the outer diameter of the filter 120 and forms a drop prevention mechanism. For example, the fuel is externally sealed by an O-ring 93. However, an external seal such as a gasket and welding may be used.

  Note that the filter 120 may be fixed in the fuel passage in the joint 100 from the upstream opening side of the fuel passage.

  A second embodiment of the present invention will be described below with reference to FIG.

  The joint 150 includes a low-pressure fuel pipe 100B that connects the low-pressure pump 51 serving as a feed pump and a suction passage 10a provided in the casing 1 of the high-pressure pump, and a fuel pipe 100C that connects the downstream side of the relief valve 55 and the low-pressure fuel pipe. A bifurcated fuel passage portion having a merging point is formed.

  The joint 150 includes a suction passage joint 151 and a mounting flange 152 that are inserted into a suction passage 10 a provided in the casing 1.

  A sealing O-ring 160 is mounted around the suction passage joint portion 151 to prevent fuel leakage. A fuel passage 155 is formed at the center. In the fuel passage 155, the filter 120 is press-fitted and fixed to the inner wall of the fuel passage 155 with the metal mesh or resin net 121 upstream, and the fixing head holder 122. The configuration of the filter 120 is the same as that of the first embodiment shown in FIGS.

  The joint portion 151 for the suction passage portion is inserted into the suction passage 10a, and the flange portion 152 is screwed and fixed to the casing portion 1 with the screw 153.

  In this embodiment, a filter is attached to the intake passage joint portion 151 of the joint 150 constituting the bifurcated fuel passage portion, so that the joint 150 and the filter 120 constituting the bifurcated fuel passage portion are integrated into a single unit. Can be handled as one part.

  According to the high pressure fuel supply pump of the above embodiment, a casing in which a suction passage for sucking fuel and a discharge passage for discharging fuel are formed, a joint for connecting a suction passage inlet of the casing and a low pressure fuel supply pipe are provided. A filter is provided in the fuel passage. Therefore, a high-pressure fuel supply pump that can simplify the casing structure, liberalize the filter size, and facilitate the replacement work when the filter is obtained is obtained.

  In addition, since a sufficient distance from the pressurizing chamber provided between the suction passage and the discharge passage to the filter is given, a high-pressure fuel supply pump capable of stabilizing the fuel flow is obtained.

  Also, when the filter is full of deposits (filtrate), it is not possible to replace only the filter. This is because the press-fitting portion of the filter expands when the filter is removed, and a new filter cannot be press-fitted.

  In this embodiment, in this case, only the joint need be replaced, and there is no need to replace the pump body.

  The passage cross-sectional area of the throttle portion for suppressing pulsation is required to have various passage cross-sectional areas depending on the type of vehicle mounted. In this embodiment, even in such a case, various types can be formed by resin molding by changing the inner diameter of the resin-made annular portion of the filter and the cross-sectional area of the protruding portion. Therefore, it is not necessary to prepare a plurality of types of metal joints having different inner diameters, and the same joint can be used for various models, and the joint can be standardized.

  The present invention can also be used for a low pressure passage joint of a fuel supply system for a diesel internal combustion engine.

It is sectional drawing of the high pressure fuel supply pump with which this invention is implemented. II-II cross-sectional enlarged view of FIG. It is a cross-sectional enlarged view of the filter, and is a cross-sectional view taken along the line AA of FIG. FIG. 4 is a bottom view of FIG. 3. It is a high-pressure fuel supply system figure. It is a partial expanded sectional view of 2nd Example of the high pressure fuel supply pump with which this invention is implemented.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Casing, 2 ... Plunger, 3 ... Lifter, 4, 5a, 6a, 202 ... Spring, 5, 5b ... Suction hole, 6 ... Discharge valve, 6b ... Discharge hole, 7 ... Cam, 10 ... Fuel intake passage, 11 ... Discharge passage, 12 ... Pressure chamber, 12a ... Pump chamber, 20 ... Cylinder, 30 ... Plunger seal,
DESCRIPTION OF SYMBOLS 40 ... Engine control unit, 50 ... Tank, 51 ... Low pressure pump, 52 ... Pressure regulator, 53 ... Common rail, 54 ... Injector, 55 ... Relief valve, 56 ... Pressure sensor, 100 ... Joint, 120 ... Filter, 121 ... Metal mesh Or, resin net, 122 ... fixing head holding body part, 123 ... annular part, 124 ... leg part, 125 ... metal ring, 200 ... solenoid, 201 ... engagement member.

Claims (4)

Includes a pulsation reducing damper chamber into the low-pressure fuel passage formed in the pump body, Bei example the filter to the low pressure fuel passage communicating with the damper chamber on the upstream side of the damper chamber,
The passage cross-sectional area of the fixing head holding body portion of the filter is configured to be smaller than the passage cross-sectional area of the low-pressure fuel passage before and after the filter ,
The filter fixing head holder is press-fitted and fixed in a joint connected to the low-pressure fuel passage formed in the pump body,
The high-pressure fuel supply pump, wherein the fixing head holding body portion for fixing the filter is fixed to the inner peripheral wall of the outlet side passage of the joint, and the filter portion is arranged toward the inlet side . In claim 1 ,
A fixing head holding body portion of the filter is an annular portion of a resin material;
A metal ring member that covers the outer periphery of the annular portion made of the resin material;
A plurality of holding legs extending in the axial direction from the annular portion made of the resin material;
A high-pressure fuel supply system or a high-pressure fuel supply pump comprising a ring-shaped portion made of the resin material and a cup-shaped metal or resin net member partially molded with a holding leg. In claim 2 ,
A high pressure fuel supply pump in which an outer periphery of the metal ring member is press-fitted and fixed to a passage inner peripheral wall in a joint connected to the low pressure fuel passage formed in the pump body. The high-pressure fuel supply pump according to claim 1 ,
The high-pressure fuel supply pump according to claim 1, wherein the filter has a cylindrical net, and the net is inserted into the joint from an end surface on the housing side of the joint .

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