High-pressure fuel pump

Abstract

High-pressure fuel pump with: a pump housing (12, 142, 192) which has a suction port (20) for defining a suction port (300), a pressure chamber (308) for drawing fuel from the suction port (300) and a delivery port (30) for defining a delivery port (310) which delivers pressurized fuel in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of the reciprocating movement of the plunger (50); a cylinder (15) for sliding support of the plunger (50); a cover (42) in combination with the pump housing (12, 142, 192) to form a fuel chamber (302), wherein the fuel chamber (302) is defined in the pump housing (12, 142, 192) at a location between the intake opening (300) and the pressure chamber (308); a valve (70); a connecting passage (304) formed in the pump housing (12, 142, 192) and connecting the fuel chamber (302) to a suction chamber (306) of the valve (70), wherein the suction chamber (306) is formed in the pump housing (12, 142, 192) and the valve (70) has a valve seat (73) and a valve element (74); and a pulsation damper (44) arranged in the fuel chamber (302), wherein the intake opening hole (20) and the fuel chamber (302) are connected to each other via a vertical hole which is formed parallel to the plunger (50) in the pump housing (12, 142, 192), characterized in that the valve (70) is an electromagnetic valve (70) for establishing and disconnecting the connection between the fuel chamber (302) and the pressure chamber (308) according to the switching-on state of the energy supply to a coil (92), the vertical hole has a filter (40) attached to it for filtering fuel supplied from the intake opening (300), at least part of the filter (40) and the pressure chamber (308) coexist on a virtual plane, which is defined as a plane perpendicular to an axis of the cylinder (15) and the high-pressure fuel pump further a fuel outlet passage (342) which the cylinder (15) connects to the fuel chamber (302) thereby and fuel escaping from the pressure chamber (308) through a sliding section between the diving piston (50) and the cylinder (15) to the fuel chamber (302).

Description

Technical field

[0001] The following refers to a high-pressure fuel pump that regulates a fuel delivery pressure through a drain valve to a predetermined pressure. State of the art

[0002] High-pressure fuel pumps are known for pressurizing fuel drawn into a pressure chamber by the reciprocating movement of a piston. When the fuel delivery pressure exceeds a predetermined pressure, a drain valve opens to reduce the fuel delivery pressure. This type of fuel pump is disclosed, for example, in JP 2003-247 474 A, JP H11-200 990 A, and JP 2004-138 062 A. In particular, JP 2003-247 474 A discloses a fuel pump with the features of the preamble of claim 1. However, manufacturing this conventional high-pressure pump, which is equipped with such a drain valve, can be extremely time-consuming. Furthermore, EP 0 604 083 B1 discloses a high-pressure fuel pump in which a drain valve is arranged in the pump inlet. The drain valve regulates the delivery pressure of an integrated low-pressure pump.JP 2003-343 395 A and JP 2004-218 547 A reveal further state of the art.

[0003] Since, according to JP 2003-247 474 A, JP H11-200 990 A, and JP 2004-138 062 A, for example, a special or exclusive hole is formed in a pump housing to receive the drain valve, the manufacturing time for forming the receiving hole for the drain valve increases. Because the drain valve is received in the exclusive hole, it may also be necessary to seal the receiving hole of the drain valve, or any gap between the receiving hole and the drain valve, with a sealing element or the like, in addition to sealing areas that differ from the receiving point of the drain valve. This leads to an increase in the number of sealing points of the drain valve, which further extends the manufacturing time for sealing.

[0004] Additionally, fuel pumps with a drain valve are located in a dedicated hole in a housing (see e.g. Fig. 2 of JP H11-200 990 A) the housing is divided into a plurality of housing elements to accommodate the drain valve. If the pump housing has a plurality of housing elements to accommodate the drain valve, then a clamping element or the like is used to assemble the housing elements together, which increases the assembly time of the pump housing.

[0005] Furthermore, a fuel outlet is provided to release the delivered fuel from the discharge valve, connecting the delivery port to a delivery port side of the discharge valve. However, it is difficult to create such a fuel outlet inside the pump housing. Therefore, manufacturing it becomes more difficult and time-consuming.

[0006] If the fuel outlet passage is designed exclusively for releasing the pumped fuel from the drain valve, the manufacturing time for forming the fuel outlet passage in the pump housing will also be longer.

[0007] In this way, the time to manufacture and seal the receiving hole in the drain valve, the time to assemble the pump housing, and the time to create the fuel outlet passage are significant, and as a result, the manufacturing time of the high-pressure fuel pump is significant.

[0008] Furthermore, reducing the size of a conventional high-pressure fuel pump can be difficult.

[0009] For example, if a drain valve is accommodated in a dedicated hole, space is provided in the pump housing to form this dedicated hole, thus increasing the size of the pump housing. Furthermore, if a gap between the dedicated hole of the drain valve and the drain valve is sealed with a sealing element, such as an O-ring, space is required for the sealing element, and therefore the size of the pump housing also increases.

[0010] Furthermore, in a structure for clamping a multitude of housing elements to accommodate the drain valve, a sealing dimension at the assembly point of the housing elements is essentially long, thereby increasing the size of the pump housing. Description of the invention; Technical problem

[0011] In light of the foregoing, a need remains for a high-pressure fuel pump that overcomes the aforementioned problems of the prior art. The present disclosure addresses this prior art need as well as other needs that would be apparent to a person skilled in the art. Technical solution

[0012] The problem is solved by a high-pressure fuel pump according to claim 1. Advantageous embodiments are disclosed in the dependent claims. Advantageous effects of the invention; Brief description of the illustrations and drawings

[0013] Further tasks, features and advantages of the present disclosure will become apparent from the following detailed description, given with reference to the accompanying drawings, in which identical parts are designated by the same reference numerals and in which: Fig. 1 a cross-sectional view of a high-pressure fuel pump according to a first embodiment; Fig. 2A is a sectional view of an intake port hole, which is a fuel pump drain valve. Fig. 1 has; Fig. 2B a sectional view of the fuel pump from Fig. 2A along line IIB-IIB is; Fig. 2C a cutaway view of the fuel pump from Fig. 2A along line IIC-IIC from Fig. 2A is; Fig. 3 a longitudinal section view of the fuel pump of Fig. 1 is; Fig. 4 is a cross-sectional view of a high-pressure fuel pump according to a second embodiment; Fig. 5A is a sectional view of an intake opening of a fuel pump according to a third embodiment including a drain valve; Fig. 5B is a perspective view showing a guide to the third embodiment; Fig. 6 is a cross-sectional view of a high-pressure fuel pump according to a fourth embodiment; Fig. 7A is a sectional view of an intake port including a drain valve in a fuel pump according to a fifth embodiment; and Fig. 7B a sectional view along line VIIB-VIIB in Fig. 7A is. Best way to implement the invention

[0014] Several exemplary embodiments will be described below with reference to the accompanying drawings. First embodiment

[0015] Fig. Figures 1 to 3 show a high-pressure fuel pump in a first embodiment of the present disclosure. A high-pressure fuel pump 10 is a pump for supplying fuel, for example, to an injector of a diesel engine or a gasoline engine. The fuel supplied by a low-pressure pump (not shown) to an intake port 300 flows through a filter 40 and is drawn, in that order, through a fuel chamber 302, a connecting passage 304, and a suction chamber 306 into a pressure chamber 308. The pressurized fuel in the pressure chamber 308 is supplied by a delivery port 310 to a fuel rail or the like. The direction of the fuel flow is indicated by an arrow at various points in the figures.

[0016] A pump housing 12 is present, formed in one piece from an iron material, such as stainless iron. A cover 42 is also present, which is coupled to the housing 12. The housing 12 has a cylinder 15 formed within it. Furthermore, the entire housing 12 is hardened to increase its hardness. In a case where the high-pressure fuel pump 10 is used in a diesel engine, the housing 12 may be formed from a non-stainless iron element. The housing 12 is also provided with a piston receptacle 14, which receives a piston 50 in such a way that it moves back and forth within it. The piston receptacle 14 is integral with the cylinder 15, which supports the piston 50 in a reciprocating manner.Additionally, the housing body 12 is provided with an intake opening 20 and a delivery opening 30 formed within it. The intake opening 20 defines the intake opening 300 and the delivery opening 30 defines the delivery opening 310.

[0017] The fuel chamber 302 is defined by a concave section 16 formed in the housing body 12 and the cover 42. The fuel chamber 302 is essentially coaxial with the plunger 50 on one side opposite the pressure chamber 308 in the axial direction of the plunger 50 and extends radially outside the pressure chamber 308.

[0018] A pulsation damper 44 is held between the cover 42 and the housing body 12. The pulsation damper 44 deforms flexibly in response to fuel pressure in the fuel chamber 302 and reduces pressure pulsation of the fuel drawn from the fuel chamber 302 to the pressure chamber 303. The connecting passage 304 connects the fuel chamber 302 to the suction chamber 306 of an electromagnetic valve 70.

[0019] The plunger 50 is supported in a reciprocating manner within the cylinder 15 of the housing body 12. The pressure chamber 308 is formed at one end in the direction of reciprocating movement of the plunger 50. The plunger 50 has an outer circumferential surface sealed by oil seals 62, 64, which are supported by a support element 60 between one side of the head 52 of the plunger 50 and one side of the cylinder 15. The oil seals 62, 64 reduce the leakage of oil from a power unit into the pressure chamber 308 and also reduce the leakage of fuel from the pressure chamber 308 into the power unit. The head 52 formed at the other end of the plunger 50 is joined to a spring seat 54. The head 52 of the plunger 50 rests against the inner bottom wall of a driver 56 as a result of a force from a spring 58.An outer bottom wall of the driver 56 slides on a (not shown) pump cam by rotating the pump cam, thereby generating a back-and-forth movement of the plunger 50.

[0020] The electromagnetic valve 70 connects / disconnects the connection between the suction chamber 306 and the pressure chamber 308 depending on the activation state of the energy supply to a coil 92. The electromagnetic valve 70 is a metering valve for metering a fuel delivery quantity by controlling the timing of the energy supply to the coil 92. The suction chamber 306 is connected to the fuel chamber 302 via the connecting passage 304.

[0021] A valve body 72 of the electromagnetic valve 70 is mounted on the housing body 12 between the suction chamber 306 and the pressure chamber 308. When a valve element 74 rests on a valve seat 73 of the valve body 72, the connection between the suction chamber 306 and the pressure chamber 308 is interrupted. A spring seat 76 is located inside the valve body 72 and is in contact with one end of a spring 78. The other end of the spring 78 is in contact with the valve element 74. The spring 78 exerts a force on the valve element 74 in such a valve closing direction that the valve element 74 is seated on the valve seat 73. The spring seat 76 is provided with a fuel port 76a, which is formed therein to connect the suction chamber 306 to the pressure chamber 308.

[0022] A stationary core 80, shaped like a cup, is present and is joined to the housing body 12 by laser welding or a similar process. A movable core 82 is located on the side of the stationary core 80 opposite the valve element 74 and faces the stationary core 80. A rod 84 is inserted through the central section of the stationary core 80. Furthermore, the rod 84 is connected to the movable core 82 by laser welding or a similar process and moves back and forth with the movable core 82. The spring 86 is in contact with one end of the rod 84 and exerts a force on the rod 84 in the direction in which the movable core 82 moves towards the stationary core 80, i.e., in the direction of the valve element 74. In a state in which the rod 84 is in contact with the valve element 74, the force of the spring 86 acts in the valve opening direction, in which the valve element 74 is moved away from the valve seat 73.

[0023] When the force of spring 86 is set to F1 and the force of spring 78 is set to F2, each force is adjusted such that F1 is less than F2 (i.e., F1 < F2). As a result of the force difference between spring 78 and spring 86, the valve element 74 is pressed in the direction in which it is seated on the valve seat 73. Therefore, the valve element 74 is biased to seat itself on the valve seat 73.

[0024] Yokes 88 and 89 cover an outer circumference of the coil 92 and form a magnetic circuit with the stationary core 80 and the movable core 82. A tubular non-magnetic element 90 is located between the stationary core 80 and the yoke 89 to prevent a short circuit of the magnetic flux between the stationary core 80 and the yoke 89. The coil 92 is wound around an outer circumference of each stationary core 80, the yoke 89, and the non-magnetic element 90. A terminal 94 is electrically connected to the coil 92 and supplies energy to the electromagnetic valve 70.

[0025] A ball 102, a spring seat 104, a spring 106, and a C-ring 108 of a delivery valve 100 are received in the delivery opening 30. The housing body 12 also serves as the valve body of the delivery valve 100, and a valve seat 110, onto which the ball 102 is placed, is formed in the housing body 12. The delivery valve 100 is located laterally to an axis of the high-pressure fuel pump 10 and radially to the central axis of the high-pressure fuel pump 10. The C-ring 108 prevents the spring seat 104 from falling out of the delivery opening 310. When the pressure in the pressure chamber 308 rises above a predetermined pressure, the ball 102 lifts off the valve seat 110 against the force of the spring 106, and high-pressure fuel in the pressure chamber 308 is delivered through the delivery opening 310.

[0026] As in Fig. As shown in Figure 1, a ball 122, a guide 124, a spring seat 126, a spring 130, a washer 132, and a C-ring 134 of the drain valve 120 are accommodated in the drain valve receiving section 22 of the intake opening 20. The drain valve receiving section 22 is coaxial with the intake opening 300 and forms at the depth of the intake opening 20. The housing body 12 also serves as the valve housing of the drain valve 120, and a valve seat 136, onto which the ball 122 is placed, is formed in the housing body 12.

[0027] As in Fig. As shown in Figure 2, the guide 124 has a cross-sectional shape and receives a force directed from the spring 130 towards the ball 122. Furthermore, the guide 124 guides the ball 122 as it slides on the drain valve receiving section 22 and moves back and forth with the ball 122. A fuel passage 320 is formed between the guide 124 and the drain valve receiving section 22.

[0028] The spring seat 126 has a plate section 127 and a rod 128. The plate section 127 rests against the C-ring 134 due to the spring force. The rod 128 extends to the guide 124. The stroke of the ball 122 is limited by the contact between the guide 124 and the rod 128. The circumference of the plate section 127 is linearly cut away, and a fuel passage 322 is formed between the plate section 127 and the drain valve receiving section 22.

[0029] The washer 132 is inserted into the rod 128 of the spring seat 126 and is held between the plate section 127 of the spring seat 126 and the spring 130. The force exerted by the spring 130 on the guide 124 and the ball 122 can be adjusted by changing the thickness or the number of washers 132. The C-ring 134 fits into the annular groove formed in an inner wall of the drain valve receiving section 22 and prevents the spring seat 126 from falling out of the drain valve receiving section 22.

[0030] The drain valve 120 is connected to the delivery port 310 by a fuel outlet passage 312 on the side of the delivery port 310. The fuel outlet passage 312 is inclined from the midpoint of the delivery port 310 towards the drain valve 120. When the fuel pressure supplied by the delivery port 310 rises above a predetermined pressure, the ball 122 lifts off the valve seat 136 against the force of the spring 130, and a portion of the fuel flows through the delivery port 310, the fuel outlet passage 312, and the drain valve 120 in that sequence, and is discharged towards the intake port 300. As a result, the delivery pressure of the fuel supplied by the delivery port 310 is reduced in such a way that it does not exceed the predetermined pressure. The valve opening pressure of the drain valve 120 is higher than that of the delivery valve 100.

[0031] Viewing the delivery opening 310 from the side towards the axis of the high-pressure fuel pump 10 along the reciprocating direction of the plunger 50, the drain valve receiving section 22 and the delivery opening hole 30 overlap axially by a distance L, as indicated by two dashed lines 400, as shown in Fig. Figure 1 shows that the drain valve 120 extends laterally relative to the axis of the high-pressure fuel pump 10 and is offset from the axis of the delivery port 30. In this embodiment, the delivery port 30 connects the pressure chamber 308 to an area outside the housing body 12 to convey fuel from the pressure chamber 308 to the delivery port 310.

[0032] Next, the operation of the high-pressure fuel pump 10 is described. (1) Intake stroke

[0033] When the plunger 50 descends to reduce the pressure in the pressure chamber 308, the valve element 74 experiences a pressure differential between the suction chamber 306 (the fuel inlet side of the valve element 74) and the pressure chamber 308 (the fuel outlet side). When the sum of the forces exerted by the valve element 74 towards the valve seat 73 due to the fuel pressure in the pressure chamber 308 and the force or load of the spring 78 becomes less than the sum of the force on the valve element 74 directed away from the valve seat 73 due to fuel pressure in the suction chamber 306 and the force of the spring 86, the valve element 74 moves away from the valve seat 73. As a result, the fuel flows through the fuel chamber 302, the connecting passage 304, and the suction chamber 306 in that order and is drawn into the pressure chamber 308.When the valve element 74 moves away from the valve seat 73, the rod 84 moves towards the valve element 74 due to the force of the spring 86, and the movable core 82 moves towards the stationary core 80. When the movable core 82 comes into contact with the stationary core 80, the movable core 82 and the rod 84 cease their movement. In the state where the movable core 82 is in contact with the stationary core 80, the tip of the rod 84 protrudes on the side of the valve element 74 that is closer to the valve element 74 than to the valve seat 73.

[0034] Additionally, before or when the piston 50 reaches bottom dead center, the energy supply to the coil 92 is switched on in a state where the variable core 82 is in contact with the stationary core 80. Since the energy supply to the coil 92 is switched on in a state where the movable core 82 is in contact with the stationary core 80, a large magnetic attraction exists between the stationary core 80 and the movable core 82 even when the voltage supplied to the coil 92 is small. Therefore, even when the voltage supplied to the coil 92 is small, the state in which the movable core 82 is in contact with the stationary core 80 can be maintained. (2) Reset cycle

[0035] Even when the plunger 50 rises from bottom dead center to top dead center, because the energy supply to the coil 42 is ON and the magnetic attraction between the stationary core 80 and the movable core 82 is acting, the movable core 82 is held in a position where it rests against the stationary core 80. That is, since the valve element 74 is blocked by the rod 84, which is to be held at the valve opening position spaced from the valve seat 73, the fuel in the pressure chamber 308 flows through the suction chamber 306 and the connecting passage 304 as the plunger 50 rises, and then returns to the fuel chamber 302. (3) Pressure application cycle

[0036] If the energy supply to coil 92 is switched off during a return stroke, then the magnetic attraction does not act between the stationary core 80 and the moving core 82. As a result, the valve element 74 moves towards the valve seat 73 (i.e., to the right). Fig. 3), which is the valve opening direction, and is then, as a result of a difference in the forces of spring 78 and spring 86 and a fluid force, when the fuel in pressure chamber 308 flows through suction chamber 306 and connecting passage 304 and back to fuel chamber 302 as the plunger 50 rises, it is seated on the valve seat 73. Therefore, the connection between suction chamber 306 and pressure chamber 308 is blocked. If the plunger 50 continues to move upwards towards top dead center under this condition, the fuel in pressure chamber 308 is pressurized, so that the fuel pressure therein increases. Then, when the fuel pressure in pressure chamber 308 exceeds a predetermined pressure, the ball 102 of the delivery valve 100 moves away from the valve seat 110 against the preload force of spring 106, thereby opening the delivery valve 100.As a result, the fuel pressurized in pressure chamber 308 is delivered from the delivery opening 310. The fuel delivered from the delivery opening 310 is fed to the (not shown) fuel rail, accumulated there, and then supplied to a fuel injector.

[0037] If the fuel pressure delivered by the delivery port 310 exceeds the valve opening pressure of the drain valve 120, then the ball 122 moves away from the valve seat 136 against the force of the spring 130, thereby opening the drain valve 120. When the drain valve 120 is open, the high pressure in the delivery port 310 flows through the fuel outlet passage 312, the fuel passages 320 and 322 of the drain valve 120, and is then released to the side of the intake port 300. As a result, the delivery pressure of the fuel sent from the delivery port 310 is reduced.

[0038] The repetition of the preceding strokes (1) to (3) causes the high-pressure fuel pump 10 to pressurize the drawn-in fuel and deliver it. The fuel delivery rate is set by controlling the timing of the energy supply to the coil 92 of the electromagnetic valve 70.

[0039] Since, according to the first embodiment, the drain valve 120 is received in the drain valve receiving section 22, which is formed at the depth of the intake opening hole 20 that defines the intake opening 300, it is not necessary to additionally form a separate hole in the housing body 12 for receiving the drain valve 122. As a result, the manufacturing time and effort for the high-pressure fuel pump 10 are reduced. Accordingly, the manufacturing costs of the high-pressure fuel pump 10 can be reduced.

[0040] Since the drain valve receiving section 22 is also formed coaxially with the intake opening 300 through the intake opening hole 20, the drain valve receiving section 22 and the intake opening 300 can be machined coaxially. Therefore, it is easier to machine out the housing body 12.

[0041] Since the housing body 12 also serves as the valve housing of the drain valve 120, the number of components of the drain valve 120 is reduced, thus enabling a reduction in the size of the housing body 20.

[0042] Since the drain valve 120 is located laterally to the axis of the fuel pump, it is possible to shorten the axial length of the high-pressure fuel pump 10. Furthermore, when the drain valve 120 opens, the fuel is discharged from the drain valve 120 to the side of the intake port 300. According to this design, a sealing element in the housing body 12 is unnecessary for accommodating the drain valve 120 in the high-pressure fuel pump 10, thus reducing the number of sealing points in the high-pressure fuel pump 10. This leads to a reduction in the number of sealing elements and a reduction in the manufacturing time required for placing and providing the sealing elements. Therefore, this results in a reduction in the manufacturing time for the high-pressure fuel pump 10 and a reduction in its manufacturing costs.Since space for placing the sealing element in the housing body 12 for the drain valve 120 in the pump housing 12 is also available, the housing body 12 and the fuel pump 10 itself can be more easily reduced in size. Furthermore, since reducing the number of sealing points also reduces the number of places where a rubber element, such as an O-ring, is used as a sealing element, it can prevent evaporated fuel from escaping through the sealing element.

[0043] Furthermore, since the drain valve 120 is located at a position spaced apart from the delivery opening hole 30, the drain valve 120 can be located on the opposite side of the housing body 12 from the delivery opening hole 30. Accordingly, the housing body 12 can be made smaller. Second embodiment

[0044] Fig. Figure 4 shows a second embodiment of the present disclosure. It should be noted that components identical to those of the first embodiment are designated with the same reference numerals.

[0045] In the second embodiment, the hardness of the cylinder 15 is ensured by selectively hardening only the cylinder 15 of a housing body 142 in a high-pressure fuel pump 140. In one embodiment, the cylinder 15 is a separate element from the other sections of the housing body 142 (i.e., it is not integrally formed with it). It must be acknowledged that, with regard to hardness, it is difficult to form the valve seats of a delivery valve 150 and a discharge valve 160 directly in the housing body 142. Therefore, in the second embodiment, the valve seat of the delivery valve 150 and the valve seat of the discharge valve 160 are formed with valve seat elements 152, 162, each of which has a greater hardness than that of the housing body 142. The valve seat elements 152, 162 are received in the delivery opening hole 30 and the discharge valve receiving section 22, respectively. Third example

[0046] Fig. 5A and Fig. Figure 5B shows a third embodiment of the present disclosure. It should be noted that components identical to those of the first embodiment are designated with the same reference numerals.

[0047] In the third embodiment, a guide 180 for guiding a ball 122 of the drain valve 170 has the shape of a cup. The guide 180 has a base 182, the contour of which is formed according to the size of the ball 122, as shown in Fig. Figure 5 shows a fitting hole 183 extending through the base 182 with a diameter smaller than that of the ball 122. The ball 122 fits into the contoured section of the base 182 and partially into the fitting hole 183. The guide 180 also has a plurality of nails 184 extending away from the ball 122. In the illustrated embodiment, there are four nails 184 spaced equally around the circumference of the base 182. The guide 180 guides the ball 122 as the nails 184 slide along the wall of the drain valve receiving section 22 during the reciprocating motion with the ball 122. Additionally, when the drain valve 170 opens, fuel is released through the spaces between the nails 184 behind the guide 180. In one embodiment, the guide 180 is formed by pressing a plate element. Fourth embodiment

[0048] Fig. Figure 6 shows a fourth embodiment of the present disclosure. It should be noted that components identical to those of the first embodiment are designated with the same reference numerals.

[0049] In a high-pressure fuel pump 190 of the fourth embodiment, the housing body 192 has a fuel outlet passage 330. The fuel outlet passage 330 provides a connection between the delivery port 310 and the drain valve 120. The fuel outlet passage 330 extends to an outer circumferential surface of the housing body 192. A sealing screw 202 is also provided, which presses a ball 200 against a step of the fuel outlet passage 330 to close the fuel outlet passage 330.

[0050] In the fourth embodiment, the fuel outlet passage 330 extends to the outer circumferential surface of the housing body 192. Thus, machining and manufacturing the fuel outlet passage 330 can be simpler compared to the structure in which the fuel outlet passage 312 extends from a center point of the delivery opening 310, as is the case in the first embodiment. Fifth embodiment

[0051] Fig. 7A and Fig. Figure 7B shows a fifth embodiment of the present disclosure. It should be noted that components identical to those of the first embodiment are designated with the same reference numerals.

[0052] In the fifth embodiment, a fuel outlet passage 340 is provided for connecting a drain valve 210 to a fuel chamber 302, allowing a portion of the supplied fuel to flow from the drain valve 210 to the fuel chamber 302, which is located in the side of an intake port 300. Since it is not necessary to discharge the supplied fuel directly from the drain valve 210 to the intake port 300, the groove for forming the fuel outlet in this embodiment is not located in a plate section 222 of a spring seat 220, as in the first embodiment. As a result, the machining and manufacturing of the spring seat 220 is simpler, and therefore the manufacturing costs of the spring seat 220 are reduced.

[0053] Furthermore, the fuel outlet passage 342 extends through a drain valve receiving section 22 and connects a plunger receiving hole 14 with the fuel chamber 302. The fuel flowing through a sliding section between a plunger 50 and a cylinder 15, and escaping from a pressure chamber 308 to the sides of the oil seals 62, 64, flows through the fuel outlet passage 342 and the drain valve 210 and is then discharged into the fuel chamber 302. A portion of the fuel outlet passage 342 is shared with the fuel outlet passage 340.

[0054] Since the fuel outlet passage 340, which discharges the fuel to the fuel chamber 302 at the opening of the drain valve 310, is partially shared with the fuel outlet passage 342, which discharges the fuel escaping from the sliding section between the cylinder 15 and the diving piston 50 to the fuel chamber 302, the manufacturing time of the fuel outlet passage and the fuel pump can be reduced. Further examples of implementation

[0055] In the aforementioned embodiments, the housing body also serves as the valve housing of the drain valve. In another embodiment, a drain valve, assembled by incorporating the valve housing as a subassembly, can be accommodated in an intake port. Even in a case where the subassembly drain valve is accommodated in the intake port, it is not necessary to further seal the intake port or any gap between the intake port and the drain valve.

[0056] In the aforementioned embodiments, the housing body also serves as the valve housing of the delivery valve. In a further embodiment, a delivery valve, which is formed as a subassembly by integrating the valve housing, can be received in a delivery opening hole. Additionally, in the preceding embodiments, the intake opening hole 20 is designed such that the outlet valve receiving section 22 is coaxial with the intake opening 300. In another embodiment, an axis of the intake opening 300 is offset from an axis of the outlet valve receiving section 22 to form the intake opening hole. Additionally, the outlet valve receiving section 22 can be designed at an angle to the intake opening 300 to form the intake opening hole.

[0057] Furthermore, in the aforementioned embodiments, the drain valve and the delivery valve are located on the same plane. In another embodiment, the drain valve is located on a plane that differs from that of the delivery valve. Accordingly, for example, one of the drain valves and the delivery valve can be located longitudinally, and the other can be located laterally. Additionally, the drain valve does not deviate from the delivery opening 310 and can be located radially to the central axis of the high-pressure fuel pump.

[0058] In another embodiment, which differs from the second embodiment, a receiving hole of the drain valve, which differs from the intake opening hole, is exclusively formed, and a fuel outlet passage for connecting the delivery opening with the side of the delivery opening of the drain valve received in the exclusive hole is formed from the outer circumferential surface of the housing body.

[0059] In yet another embodiment, which differs from the fifth embodiment, a receiving hole of the drain valve, which differs from the intake opening hole, is exclusively formed, and a fuel outlet passage for releasing fuel from a plunger receiving hole is used jointly with a fuel outlet passage for releasing the conveyed fuel from the drain valve received in the exclusive hole.

[0060] In an embodiment that differs from the fifth embodiment, the fuel outlet passage 332 for releasing fuel from the plunger receiving hole 14 is not used together with the fuel outlet passage 330 for releasing the delivered fuel from the drain valve 210 to the fuel chamber 302 and it is designed in a path that differs from the fuel outlet passage 330.

[0061] While the selected embodiments were chosen merely to illustrate the present disclosure, it is evident to the person skilled in the art from this disclosure that various changes and modifications can be made without deviating from the scope of disclosure as defined in the accompanying claims. Furthermore, the present description of the embodiments according to the present disclosure is given for illustrative purposes only and does not serve the purpose of limiting the disclosure defined in the accompanying claims and their equivalents.

[0062] A high-pressure fuel pump is disclosed, comprising a pump housing (12, 142, 192) with a suction port (20) for defining a suction port (300), a pressure chamber (308) for drawing fuel from the suction port (300), and a delivery port (30) for defining a delivery port (310) that delivers pressurized fuel in the pressure chamber (308). The fuel pump also has a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) by means of the reciprocating movement of the plunger (50). Furthermore, the fuel pump has a drain valve (120, 160, 170, 210) provided in the intake port (20), wherein the drain valve (120, 160, 170, 210) opens when the delivery pressure of the fuel sent from the delivery port (310) exceeds a predetermined pressure, thereby reducing the delivery pressure of the fuel.

[0063] The following items of the parent application with file number 10 2007 063 239.4 constitute the original disclosure of the divisional application. 1. High-pressure fuel pump with: a pump housing (12, 142, 192) which has a suction port (20) for defining a suction port (300), a pressure chamber (308) for drawing fuel from the suction port (300) and a delivery port (30) for defining a delivery port (310) which delivers pressurized fuel in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of the reciprocating movement of the plunger (50); and , a drain valve (120, 160, 170, 210) provided in the intake port (20), wherein the drain valve (120, 160, 170, 210) opens when the delivery pressure of the fuel supplied by the delivery port (310) exceeds a predetermined pressure, thereby reducing the delivery pressure of the fuel. 2. High-pressure fuel pump according to Item 1, wherein the pump housing (12, 192) also serves as a valve housing of the drain valve (120, 170, 210). 3. High-pressure fuel pump according to Item 1, wherein a drain valve receiving section (22) of the intake opening hole (20) for receiving the drain valve (120, 170, 210) axially overlaps the delivery opening hole (30). 4. High-pressure fuel pump according to Item 1, wherein the drain valve (120) is offset laterally from an axis of the high-pressure fuel pump (10). 5. High-pressure fuel pump according to item 1, wherein the drain valve (120) is axially offset from the delivery opening hole (30). 6. High-pressure fuel pump according to Item 1, wherein the pump housing (192) further comprises a fuel outlet passage (330) extending from an outer circumferential surface of the pump housing (192) to connect the delivery port (310) to a delivery port side of the drain valve (120). 7. High-pressure fuel pump according to Item 1, wherein the pump housing (12, 142, 192) further comprises a fuel chamber (302) between the intake opening (300) and the pressure chamber (308), wherein a fuel outlet passage (340) provides a connection between a plunger receiving hole (14) accommodating the plunger 50 and the fuel chamber (302), wherein a fuel outlet passage (342) provides a connection between the drain valve (210) and the fuel chamber (302), and wherein the fuel outlet passage (340) and the fuel outlet passage (342) are used together. 8. High-pressure fuel pump with: a pump housing (192) which has a suction opening (300), a pressure chamber (308) for drawing fuel from the suction opening (300) and a delivery opening (310) for delivering fuel pressurized in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of the reciprocating movement of the plunger (50); and a drain valve (120) which is received in a receiving hole of the pump housing (192), wherein the drain valve (120) opens when a delivery pressure of the fuel delivered by the delivery port (310) exceeds a predetermined pressure, thereby reducing the delivery pressure of the fuel, wherein the pump housing (192) further has a fuel outlet passage (330) which extends from an outer circumferential surface of the pump housing (192) to connect the delivery opening (310) with a delivery opening side of the outlet valve (120). 9. High-pressure fuel pump with: a pump housing (12) which has a suction opening (300), a pressure chamber (308) for drawing fuel from the suction opening (300), a fuel chamber (302) formed between the suction opening (300) and the pressure chamber (308), and a delivery opening (310) for delivering the fuel pressurized in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of a reciprocating movement of the plunger (50); and a drain valve (210) which is received in a receiving hole of the pump housing (12), wherein the drain valve (210) opens when a delivery pressure of the fuel delivered by the delivery port (310) exceeds a predetermined pressure, thereby reducing the delivery pressure of the fuel, wherein a fuel outlet passage (340) provides a connection between a plunger receiving hole (14) accommodating the plunger (50) and the fuel chamber (302), wherein a fuel outlet passage (342) provides a connection between the drain valve (210) and the fuel chamber (302), and wherein the fuel outlet passage (340) and the fuel outlet passage (342) are used together. 10. High-pressure fuel pump with: a pump housing (12, 142, 192) which has a suction port (20) for defining a suction port (300), a pressure chamber (308) for drawing fuel from the suction port (300) and a delivery port (30) for defining a delivery port (310) which delivers pressurized fuel in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of the reciprocating movement of the plunger (50); and, a drain valve (120, 160, 170, 210) which opens to reduce the delivery pressure of the fuel delivered by the delivery port (310) when the delivery pressure of the fuel exceeds a predetermined pressure, and a plunger receiving hole provided on the opposite side of the pressure chamber (308) and variably changes the volume of the plunger receiving hole according to a sliding movement of the plunger (50), wherein the pump housing further comprises a fuel chamber (302) which is formed at a point between the intake opening (300) and the pressure chamber (308), and a fuel outlet passage that allows a connection between the fuel chamber and the pressure chamber, is inclined relative to an axis of the diving piston and approximates the axis of the diving piston at a diving piston receiving hole-side end of the fuel outlet passage. 11. High-pressure fuel pump according to item 10, wherein The fuel outlet passage has a first passage extending parallel to the axis of the plunger and having an opening in the fuel chamber, and a second passage that approaches the axis of the plunger at the plunger receiving hole side end and has an opening in the plunger receiving hole, and The first passage has a valve chamber to accommodate the drain valve. 12. High-pressure fuel pump according to item 10 or 11, wherein The inner diameter of the first passage is larger than the inner diameter of the second passage.

Claims

[1] High-pressure fuel pump with: a pump housing (12, 142, 192) which has a suction port (20) for defining a suction port (300), a pressure chamber (308) for drawing fuel from the suction port (300) and a delivery port (30) for defining a delivery port (310) which delivers pressurized fuel in the pressure chamber (308); a plunger (50) for pressurizing the fuel drawn into the pressure chamber (308) as a result of the reciprocating movement of the plunger (50); a cylinder (15) for sliding support of the plunger (50); a cover (42) in combination with the pump housing (12, 142, 192) to form a fuel chamber (302), wherein the fuel chamber (302) is defined in the pump housing (12, 142, 192) at a location between the intake opening (300) and the pressure chamber (308); a valve (70); a connecting passage (304) formed in the pump housing (12, 142, 192) and connecting the fuel chamber (302) to a suction chamber (306) of the valve (70), wherein the suction chamber (306) is formed in the pump housing (12, 142, 192) and the valve (70) has a valve seat (73) and a valve element (74); and a pulsation damper (44) arranged in the fuel chamber (302), wherein the intake opening hole (20) and the fuel chamber (302) are connected to each other via a vertical hole which is formed parallel to the plunger (50) in the pump housing (12, 142, 192), characterized by , that the valve (70) is an electromagnetic valve (70) for establishing and disconnecting the connection between the fuel chamber (302) and the pressure chamber (308) according to the switching-on state of the energy supply to a coil (92), the vertical hole has a filter (40) attached to it for filtering fuel supplied from the intake opening (300), at least part of the filter (40) and the pressure chamber (308) coexist on a virtual plane, which is defined as a plane perpendicular to an axis of the cylinder (15) and the high-pressure fuel pump further a fuel outlet passage (342) which the cylinder (15) connects to the fuel chamber (302) thereby and fuel escaping from the pressure chamber (308) through a sliding section between the diving piston (50) and the cylinder (15) to the fuel chamber (302). [2] High-pressure fuel pump according to claim 1, wherein the part of the filter (40) is arranged in the suction opening hole (20). [3] High-pressure fuel pump according to claim 1, wherein the vertical hole at one end near a fuel chamber has a larger diameter than at the other end near the intake opening hole (20). [4] High-pressure fuel pump according to claim 1, further comprising: a drain valve (210) which opens to reduce the feed pressure of the fuel sent from the feed port (310) when the feed pressure of the fuel exceeds a predetermined pressure, wherein the drain valve (210) is located in a space of the pump housing (12, 142, 192) which is connected to the fuel chamber (302) at the time of opening of the electromagnetic valve (70). [5] High-pressure fuel pump according to claim 1, wherein the filter (40) has an outer element covering its mesh section. [6] High-pressure fuel pump according to claim 1, wherein the pump housing (12, 142, 192) has a fuel outlet passage (312, 330) to connect the fuel chamber (302) to a plunger receiving hole (14) which is arranged to receive the plunger (50) on a side of the pressure chamber (308) opposite the cylinder (15), and the plunger (50) has a large diameter section that slides on the cylinder (15) and a small diameter section in the plunger receiving hole (14), the large diameter section being positioned on one side of the pressure chamber (308) with respect to the position of the small diameter section. [7] High-pressure fuel pump according to claim 6, wherein the fuel outlet passage (330) is connected perpendicular to the intake opening hole (20).

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