Valve system of vehicle fuel pump

Abstract

A valve system of a vehicle fuel pump includes: a reservoir cup disposed within a fuel tank storing fuel in the reservoir cup; a fuel pump configured to pump fuel from the reservoir cup to the engine while supplying fuel to a jet pump through a first discharge port; a jet pump configured to charge the reservoir cup with fuel by drawing fuel from the fuel tank by using a pressure of fuel supplied by the fuel pump; and a jet pump control valve disposed on the first discharge port and configured to control a flow of fuel discharged from the fuel pump to the jet pump.

Claims

1. A valve system of a vehicle fuel pump, the valve system comprising: a reservoir cup disposed within a fuel tank storing fuel in the reservoir cup; a fuel pump configured to pump fuel from the reservoir cup to an engine while supplying fuel to a jet pump through a first discharge port of the fuel pump; the jet pump configured to charge the reservoir cup with fuel by drawing fuel from the fuel tank by using a pressure of fuel supplied by the fuel pump; and a jet pump control valve disposed on the first discharge port and configured to control a flow of fuel discharged from the fuel pump to the jet pump, wherein, when the engine is on and a pressure of fuel discharged from the fuel pump to the engine is increased to reach a first set pressure, the jet pump control valve opens a jet pump flow path connecting the jet pump and the first discharge port of the fuel pump, and maintains the jet pump flow path in a closed state before reaching the first set pressure, and wherein, when the engine is off and the pressure of fuel discharged from the fuel pump to the jet pump is reduced to reach a second set pressure determined to be smaller than the first set pressure, the jet pump control valve closes the jet pump flow path, and maintains the open jet pump flow path when the pressure of fuel discharged from the fuel pump to the jet pump is at a pressure value between the first set pressure and the second set pressure, wherein the jet pump control valve comprises: a first valve housing, in which a plunger lift path having a predetermined height is defined, wherein the jet pump flow path is configured to be connected to a middle position of the plunger lift path; a plunger disposed on the plunger lift path in a liftable manner so as to open and close the jet pump flow path depending on a position on the plunger lift path; a second valve housing, in which a piston lift path having a predetermined height is defined, having an open hole defined on a first sidewall portion of the second valve housing; a piston disposed on the piston lift path in a liftable manner and configured to be integrally connected to the plunger via a lift bar; an elastic member arranged between a bottom surface of a top end of the second valve housing and a top surface of the piston, the elastic member configured to be compressed when the plunger moves upwards; and a foldable leaf spring disposed on the top surface of the piston and arranged between the piston and the elastic member, and configured to restrain the jet pump flow path from being opened by a pressure of fuel smaller than the first set pressure when the engine is on.

2. The valve system according to claim 1, wherein the foldable leaf spring comprises: a horizontal leaf spring portion disposed in the piston lift path to extend in a direction perpendicular to a direction in which the piston is configured to be lifted up and down, with the elastic member being disposed on a top surface of the horizontal leaf spring portion; a vertical leaf spring portion configured to be attached to a first end of the horizontal leaf spring portion and disposed in the piston lift path in the direction in which the piston is lifted up and down, with a bottom end of the vertical leaf spring portion being fixedly disposed on the top surface of the piston; and a folding leaf spring portion configured to be integrally disposed on a second end portion of the horizontal leaf spring portion in a foldable manner and disposed in the piston lift path to extend in the direction in which the piston is lifted up and down, with a flange being integrally disposed on a bottom end of the folding leaf spring portion to extend through and held by the open hole.

3. The valve system according to claim 2, wherein, when the folding leaf spring portion pivots toward a bottom surface of the vertical leaf spring portion about a second end portion of the horizontal leaf spring portion due to a pressure of fuel applied to the plunger by the fuel pump, the plunger is released and detached from the open hole and is configured to move upwards in the plunger lift path in a direction of opening the jet pump flow path.

4. The valve system according to claim 2, wherein the foldable leaf spring further comprises an inner spring arranged between the vertical leaf spring portion and the folding leaf spring portion, the inner spring being configured to be compressed when the folding leaf spring portion pivots toward the bottom surface of the vertical leaf spring portion.

5. The valve system according to claim 3, wherein the first set pressure is a value obtained by adding a pressure of fuel for compressive deformation of the elastic member and a pressure of fuel for folding deformation of the foldable leaf spring.

6. The valve system according to claim 2, wherein the plunger lift path comprises: an upper lift path in which the plunger is located to open the jet pump flow path; and a lower lift path in which the plunger is located to close the jet pump flow path.

7. The valve system according to claim 6, wherein, when the pressure of fuel discharged to the jet pump at start of the engine is equal to or greater than the first set pressure, the jet pump control valve causes the flange of the foldable leaf spring to be detached and released from the open hole and the plunger to be located in the upper lift path so that the jet pump flow path is opened.

8. The valve system according to claim 6, wherein, when the pressure of fuel discharged to the jet pump at start of the engine is smaller than the first set pressure, the jet pump control valve causes the flange of the foldable leaf spring to be located in and held by the open hole and the plunger to be located in the lower lift path so that the jet pump flow path remains in a closed position.

9. The valve system according to claim 6, wherein, when the pressure of fuel discharged to the jet pump is reduced to be smaller than the first set pressure and is greater than the second set pressure after the jet pump path is opened, the jet pump control valve causes the flange of the foldable leaf spring to remain released from the open hole and the plunger to remain in the upper lift path so that the jet pump flow path remains in an opened position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objectives, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:

(2) FIG. 1 is a conceptual view illustrating a fuel supply system according to an example of the related art;

(3) FIG. 2 is a conceptual view illustrating a fuel supply system according to another example of the related art;

(4) FIG. 3 is a graph illustrating cold startability of an engine in relation to the fuel supply system of the related art;

(5) FIG. 4 is a configuration view illustrating a valve system of a fuel pump according to an embodiment of the present disclosure;

(6) FIGS. 5 to 7 illustrate operating states of the jet pump control valve according to an embodiment of the present disclosure; and

(7) FIG. 8 is a graph illustrating a result of evaluating cold startability of the valve system of the present disclosure and cold startability of the valve system of the related art.

DETAILED DESCRIPTION

(8) Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings.

(9) In the accompanying drawings, FIG. 4 illustrates a vehicle fuel supply system in which a valve system of a fuel pump according to an embodiment of the present disclosure is used.

(10) As illustrated in FIG. 4, the vehicle fuel supply system may include: a fuel tank 100 storing fuel therein; a reservoir cup 110 disposed on the bottom within the fuel tank 100 to be continuously charged with fuel from the fuel tank 100; a fuel pump 130 pumping fuel from the reservoir cup 110 to the engine while supplying fuel to a jet pump 120; a fuel filter 140 disposed within the reservoir cup 110 to filter fuel supplied to the engine; and the like.

(11) The fuel tank 100 may be a saddle-shaped fuel tank in which a first fuel storage space 101 and a second fuel storage space 102 for storing fuel are separated from each other.

(12) In a case in which the fuel supply system includes the saddle-shaped fuel tank, the reservoir cup 110 is disposed on the bottom of the first fuel storage space 101, as illustrated in FIG. 4, so as to be continuously supplied and charged with fuel from the first fuel storage space 101. In addition, a first jet pump 121 is disposed on the bottom of the reservoir cup 110 to charge the reservoir cup 110 with fuel by drawing fuel from the first fuel storage space 101, and a second jet pump 122 is mounted on an inner portion of the reservoir cup 110 to charge the reservoir cup 110 with fuel from the second fuel storage space 102 by drawing fuel from the second fuel storage space 102.

(13) In the fuel supply system, when fuel discharged from the fuel pump 130 is pumped to the engine in response to the fuel pump 130 being driven to drive the engine, fuel is discharged toward the first jet pump 121 and the second jet pump 122. As fuel discharged from the fuel pump 130 is supplied to the jet pump 120, fuel may easily flow from the first fuel storage space 101 of the fuel tank 100 into the reservoir cup 110 in response to vacuum suction pumping of the first jet pump 121, and fuel may easily flow from the second fuel storage space 102 of the fuel tank 100 into the reservoir cup 110 in response to vacuum suction pumping of the second jet pump 122.

(14) The fuel pump 130 is provided with a first discharge port 131 for discharging fuel from the reservoir cup 110 toward the jet pump 120 and a second discharge port 132 for discharging fuel from the reservoir cup 110 toward the engine. When the fuel pump 130 pumps fuel from the reservoir cup 110 to the engine through the second discharge port 132, the fuel pump 130 also supplies fuel to the jet pump 120 through the first discharge port 131.

(15) The first jet pump 121 and the second jet pump 122 may charge the reservoir cup 110 with fuel by drawing fuel from the fuel tank 100, due to the pressure of fuel supplied through the second discharge port 132 by the fuel pump 130.

(16) According to the present disclosure, a jet pump control valve 200 is mounted on the first discharge port 131 of the fuel pump 130.

(17) The jet pump control valve 200 is configured to be able to control a flow of fuel discharged from the fuel pump 130 toward the jet pump 120 by opening and closing a jet pump flow path 214 connecting the jet pump 120 and the first discharge port 131 of the fuel pump 130.

(18) The jet pump control valve 200 may operate in an open mode or a closed mode, depending on the pressure of fuel discharged by the fuel pump 130 through the first discharge port 131.

(19) As illustrated in FIG. 4, the jet pump control valve 200 is configured to open and close the jet pump flow path 214. When the engine is started and the pressure of fuel discharged from the fuel pump 130 to the jet pump 120 is increased to reach a first set pressure, the jet pump control valve 200 opens the jet pump flow path 214. When the engine is stopped and the pressure of fuel discharged from the fuel pump 130 to the jet pump 120 is reduced to reach a second set pressure, the jet pump control valve 200 closes the jet pump flow path 214.

(20) That is, the jet pump control valve 200 is configured to maintain the jet pump flow path 214 in the closed position before the pressure of fuel supplied by the fuel pump 130 to the engine and the jet pump 120 reaches the first set pressure.

(21) In the operation of the fuel pump 130, only when the pressure of fuel supplied by the fuel pump 130 to the engine reaches a set pressure, the start (in particular, cold start) of the engine may be facilitated.

(22) The first set pressure is determined to be a fuel pressure value in the start of the engine in order to facilitate the start of the engine. For example, the first set pressure may be set to be in the range of from 4.0 to 5.0 bars.

(23) The second set pressure is determined as a fuel pressure value at which the jet pump control valve 200 is converted from the open mode to the closed mode. That is, the second set pressure is a fuel pressure value determined to close the jet pump control valve 200 after the start of the engine. The second set pressure is determined as a value smaller than the first set pressure. Specifically, the set pressure may be set to be a pressure value smaller than 2.5 bars.

(24) In addition, the jet pump flow path 214 is a flow path connecting the inlet port of the jet pump 120 and the first discharge port 131 of the fuel pump 130.

(25) The jet pump control valve 200 includes a first valve housing 210 and a second valve housing 220 as a skeletal body to perform opening/closing operations in the above-described conditions. A plunger lift path 212 having a predetermined height is provided within the first valve housing 210, while a piston lift path 222 having a predetermined height is provided within the second valve housing 220.

(26) The first valve housing 210 has the jet pump flow path 214 connected to a middle position of the plunger lift path 212, and the bottom of the first valve housing 210 communicates with the first discharge port 131 of the fuel pump 130.

(27) The jet pump flow path 214 extends from the outer portion of the first valve housing 210 and is connected to the plunger lift path 212 via one end.

(28) The plunger 230 is mounted on the plunger lift path 212 such that the plunger 230 may be lifted up and down so as to open and close the jet pump flow path 214.

(29) The plunger 230 is configured to open and close the jet pump flow path 214, depending on the position of the plunger lift path 212. In this regard, the plunger 230 is disposed in the plunger lift path 212 to divide the plunger lift path 212 into two sections, i.e. the upper lift path 212a and the lower lift path 212b.

(30) The plunger 230 moves toward the upper lift path 212a when sliding upwards to open the jet pump flow path 214. When positioned in the upper lift path 212a, the plunger 230 opens the jet pump flow path 214. In addition, the plunger 230 moves toward the lower lift path 212b when sliding downwards to close the jet pump flow path 214. When positioned in the lower lift path 212b, the plunger 230 closes the jet pump flow path 214.

(31) That is, the plunger 230 is located in the upper lift path 212a when opening the jet pump flow path 214. The plunger 230 is located in the lower lift path 212b when closing the jet pump flow path 214.

(32) In other words, the plunger 230 has a first side portion 230a disposed within the plunger lift path 212, at the side of the jet pump flow path 214. The first side portion 230a closes or opens the jet pump flow path 214, depending on the moving position.

(33) The second valve housing 220 is disposed above the first valve housing 210, and the piston lift path 222 provided within the second valve housing 220 may communicate with the plunger lift path 212 of the first valve housing 210.

(34) The piston 240 is mounted on the piston lift path 222 such that the piston 240 may be lifted up and down.

(35) The piston 240 is configured such that the piston 240 may slide up and down along the inner wall surface of the second valve housing 220 in the piston lift path 222. The piston 240 is connected to the plunger 230, located in the plunger lift path 212, via a lift bar 242 such that the piston 240 moves integrally with the plunger 230.

(36) When the piston 240 is located on the lowermost portion of the piston lift path 222, the plunger 230 is located on the uppermost portion of the lower lift path 212b to close the jet pump flow path 214.

(37) That is, when the piston 240 touches the bottom surface of the second valve housing 220, the plunger 230 is located on the highest position of an area, in which the jet pump flow path 214 may be closed, in the plunger lift path 212.

(38) In other words, when the plunger 230 moves downwards due to the pressure of fuel discharged from the first discharge port 131 of the fuel pump 130 being equal to or lower than the second set pressure, the bottom surface of the second valve housing 220 may limit a distance by which the piston 240 moves downwards, thereby allowing the plunger 230 to reliably close the jet pump flow path 214 and preventing the plunger 230 from further moving downwards and opening the jet pump flow path 214.

(39) In addition, an elastic member 250 and a foldable leaf spring 260 are mounted on the piston lift path 222, between the bottom surface 220b of the top end of the second valve housing 220 and the top surface 240a of the piston 240.

(40) The elastic member 250 may be elastically compressed by the pressure of fuel supplied to the bottom of the plunger 230 by the fuel pump 130. The elastic member 250 is disposed in the piston lift path 222 such that the elastic member 250 maybe compressed or restored in a lifting direction of the piston 240, i.e. a direction in which the piston 240 is lifted up and down.

(41) Specifically, the elastic member 250 is mounted between the bottom surface 220b of the top end of the second valve housing 220 and the top end of the foldable leaf spring 260, such that the elastic member 250 is compressed during upward movement of the piston 240 and is restored during downward movement of the piston 240.

(42) In addition, the foldable leaf spring 260 is mounted on the top surface of the piston 240, between the piston 240 and the elastic member 250. The foldable leaf spring 260 is configured to restrain the jet pump flow path 214 from being opened by a pressure of fuel smaller than the first set pressure.

(43) In other words, in a case in which the pressure of fuel applied to the plunger 230 is smaller than the first set pressure while being greater than the second set pressure, the foldable leaf spring 260 restrains the plunger 230 from moving upwards in the plunger lift path 212 and opening the jet pump flow path 214.

(44) In this regard, the foldable leaf spring 260 includes a vertical leaf spring portion 262, a horizontal leaf spring portion 264, and a folding leaf spring portion 266, each of which is implemented as an elastic leaf spring member.

(45) The vertical leaf spring portion 262 is disposed in the piston lift path 222 to extend in the lifting direction of the piston 240, and is disposed below the elastic member 250 with the bottom end of the vertical leaf spring portion 262 being fixedly mounted on the top surface 240a of the piston 240.

(46) The top end of the vertical leaf spring portion 262 is fixedly attached to a first end portion 264a of the horizontal leaf spring portion 264.

(47) The horizontal leaf spring portion 264 is disposed in the piston lift path 222 to extend in a direction (i.e. a horizontal direction) perpendicular to the lifting direction of the piston 240, and the elastic member 250 is disposed on the top surface of the horizontal leaf spring portion 264.

(48) In addition, the folding leaf spring portion 266 is disposed in the piston lift path 222 to extend in the lifting direction of the piston 240, and is integrally provided on a second end portion 264b of the horizontal leaf spring portion 264 in a foldable manner.

(49) In other words, the folding leaf spring portion 266 integrally extends from the second end portion 264b of the horizontal leaf spring portion 264 to be disposed perpendicularly to the horizontal leaf spring portion 264.

(50) When the plunger 230 is moved upwards, the folding leaf spring portion 266 allows the jet pump flow path 214 to be opened while being folded toward the horizontal leaf spring portion 264. Here, the top end of the folding leaf spring portion 266 integrally connected to the second end portion 264b of the horizontal leaf spring portion 264 may be a bent portion of the foldable leaf spring 260.

(51) In other words, when the pressure of fuel applied to the plunger 230 reaches the first set pressure, the folding leaf spring portion 266 is folded by pivoting toward the bottom surface of the horizontal leaf spring portion 264 about the second end portion 264b of the horizontal leaf spring portion 264 serving as a hinge point.

(52) The folding leaf spring portion 266 has a flange 266a integrally provided on the bottom end thereof. The flange 266a is inserted into and held by an open hole 224 of the second valve housing 220. The open hole 224 is provided on a first sidewall portion 220a of the second valve housing 220 to be disposed on a middle position between the first sidewall portion 220a and the piston lift path 222.

(53) While the flange 266a is illustrated as being disposed perpendicularly to the folding leaf spring portion 266 in FIG. 4, the flange 266a may be disposed at an obtuse angle with respect to the folding leaf spring portion 266 when the shape of the open hole 224 is changed.

(54) The flange 266a is provided to extend from the bottom end of the folding leaf spring portion 266 in a direction opposite to the vertical leaf spring portion 262. The flange 266a remains held by the open hole 224 before the pressure of fuel applied to the plunger 230 reaches the first set pressure.

(55) When the folding leaf spring portion 266 is folded by pivoting toward the bottom surface of the horizontal leaf spring portion 264 about the second end portion 264b of the horizontal leaf spring portion 264, the flange 266a is released from the open hole 224.

(56) When the flange 266a is detached and released from the open hole 224, the foldable leaf spring 260 allows the plunger 230 to move upwards.

(57) The foldable leaf spring 260 having the above-described configuration restrains the upward movement of the plunger 230 for opening the jet pump flow path 214 when the pressure of fuel applied to the bottom surface of the plunger 230 is smaller than a sum (i.e. third fuel pressure) obtaining by adding the first fuel pressure and the pressure of fuel (i.e. second fuel pressure) for the folding of the foldable leaf spring 260, even in a case where the pressure of fuel applied to the bottom surface of the plunger 230 is greater than the pressure of fuel (i.e. first fuel pressure) for compressive deformation of the elastic member 250.

(58) The third fuel pressure is a value obtained by adding the first fuel pressure for compressive deformation of the elastic member 250 and the second fuel pressure for folding deformation of the foldable leaf spring 260. The third fuel pressure is set as a minimum pressure value of fuel applied to the plunger 230 by the fuel pump 130 for the opening operation of the jet pump control valve 200.

(59) The third fuel pressure may be determined to be a value equal to or greater than an engine start reference fuel pressure (i.e. the first set pressure) supplied to the engine by the fuel pump 130.

(60) For example, the minimum fuel pressure value applied to the plunger 230 by the fuel pump 130 for the opening operation of the jet pump control valve 200 may be set to be in the range of 4.5±0.5 bars. The maximum fuel pressure value for the closing operation of the jet pump control valve 200 may be set to be in the range of 2.0±0.5 bars.

(61) In addition, the foldable leaf spring 260 may further include an inner spring 268 disposed between the vertical leaf spring portion 262 and the folding leaf spring portion 266.

(62) The inner spring 268 is configured to press the folding leaf spring portion 266 in the piston lift path 222 toward the first sidewall portion 220a of the second valve housing 220. The inner spring 268 is elastically compressed when the folding leaf spring portion 266 is folded toward the horizontal leaf spring portion 264.

(63) In addition, when the plunger 230 moves downwards to close the entrance of the jet pump flow path 214, the inner spring 268 may assist in the restoration of the shape of the foldable leaf spring 260 and the restoration of the position of the folding leaf spring portion 266.

(64) When the plunger 230 moves downwards to a position in which the entrance of the jet pump flow path 214 is closed, the folding leaf spring portion 266 may return toward the first sidewall portion 220a of the second valve housing 220 due to the elasticity thereof while restoring the flange 266a into the open hole 224. Due to the assistance of the inner spring 268, the folding leaf spring portion 266 may more easily return toward the first sidewall portion 220a while restoring the flange 266a into the open hole 224.

(65) Here, operating states of the fuel system of a vehicle pump valve having the above-described configuration will be described hereinafter with reference to FIGS. 5 to 7.

(66) FIGS. 5 to 7 illustrate operating states of the jet pump control valve according to the present disclosure. FIG. 5 illustrates a valve operating state before the pressure of fuel supplied to the engine by the fuel pump in the start of the engine reaches the first set pressure, FIG. 6 illustrates a valve operating state after the pressure of fuel supplied to the engine by the fuel pump in the start of the engine has reached the first set pressure, and FIG. 7 illustrates a valve operating state when after the pressure of fuel supplied to the engine by the fuel pump in the stopping of the engine has reached the first set pressure.

(67) As illustrated in FIG. 5, even in a case where the pressure of fuel discharged from the fuel pump 130 in the start of the engine is applied to the plunger 230, when the pressure of fuel applied to the plunger 230 is smaller than the first set pressure for opening the jet pump flow path 214, the plunger 230 maintains the jet pump flow path 214 in the closed position.

(68) Accordingly, the supply of fuel to the jet pump 120 is prevented until the pressure of fuel supplied to the engine 300 reaches the first set pressure for appropriate start of the engine 300, and only a fuel line connecting the fuel pump 130 and the engine 300 is opened to supply fuel from the reservoir cup 110 to the engine 300. Consequently, a loss in the flow rate of fuel, flowing toward the jet pump 120, is prevented, thereby reducing a time in which the pressure of fuel increases during the start of the engine.

(69) Afterwards, when the pressure of fuel discharged from the fuel pump 130 to the engine 300 is increased to reach the first set pressure, the pressure of fuel discharged from the fuel pump 130 to be applied to the plunger 230 also reaches the first set pressure.

(70) As illustrated in FIG. 6, when the pressure of fuel applied to the plunger 230 is equal to or greater than the first set pressure, the flange 266a of the foldable leaf spring 260 is detached from the open hole 224 of the second valve housing 220, so that the plunger 230 moves upwards. With the plunger 230 moving upwards while compressing the elastic member 250, the jet pump flow path 214 is opened.

(71) Referring to FIG. 8, comparing to a related-art case in which a time taken for the pressure of fuel supplied to the engine by the fuel pump to be increased to the first set pressure in a cold start of the engine is about 1 second, the disclosure may reduce the time to about 250 ms. Consequently, the engine may be rapidly and easily started even in the cold start, thereby improving cold startability of the engine.

(72) In addition, after the jet pump flow path 214 is opened, when the pressure of fuel supplied to the jet pump 120 is greater than the second set pressure even though being smaller than the first set pressure, the compressed state of the elastic member 250 is maintained by the pressure of fuel exceeding the second set pressure (i.e. the pressure for compressive deformation of the elastic member), since the flange 266a of the foldable leaf spring 260 has already been released from the open hole 224. Consequently, the plunger 230 is continuously located in the upper lift path 212, so that the jet pump flow path 214 remains in the opened position.

(73) In other words, after the jet pump flow path 214 is opened, when the pressure of fuel applied to the plunger 230 is greater than the second set pressure, the compressed state of the elastic member 250 is maintained, and thus, the opened positioned of the jet pump flow path 214 is maintained.

(74) In addition, as the operation of the fuel pump 130 is stopped when the engine is stopped, the pressure of fuel applied to the plunger 230 is reduced to reach the second set pressure, the plunger 230 is moved downwards due to the restoring force of the elastic member 250 to close the jet pump flow path 214, as illustrated in FIG. 7.

(75) Although the embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, improvements, additions, and substitutions are possible, without departing from the scope and spirit of the present disclosure as disclosed in the accompanying claims.