Valve systems for vehicle fuel pumps

Abstract

The present invention discloses a valve system for a vehicle fuel pump, which includes: a liquid storage cup, a fuel pump, an injection pump and an injection pump control valve, wherein the liquid storage cup is arranged in a fuel tank that stores fuel in the liquid storage cup; the fuel pump is configured to pump fuel from the liquid storage cup to an engine and simultaneously supply fuel to the injection pump through a first discharge port; the injection pump is configured to fill the liquid storage cup with fuel by drawing fuel from a fuel tank using the pressure of the fuel supplied by the fuel pump; the injection pump control valve is arranged on the first discharge port and is configured to control the flow of fuel discharged from the fuel pump to the injection pump.

Description

Technical Field

[0001] The present invention generally relates to a valve system for a vehicle fuel pump, and more particularly, to a valve system for a vehicle fuel pump that can reduce engine starting time to improve cold starting capability. Background Art

[0002] Generally, the fuel supply system of a vehicle is a system for appropriately supplying the required fuel to the engine under any driving conditions. The fuel supply system is one of the main factors that determine the output power and performance of the engine.

[0003] In recent years, in order to increase the output power of the engine and improve the engine performance under various driving conditions, an injection pump system is used, which can appropriately fill the reservoir cup of the fuel tank with fuel when the engine consumes the maximum fuel flow.

[0004] In the accompanying drawings, Figure 1 is a conceptual diagram illustrating a fuel supply system according to an example of the related art.

[0005] refer to Figure 1 The fuel supply system of the related art includes: an integral fuel tank 10, a reservoir cup 11, a fuel pump 13, a fuel filter 14, an injection pump 12, etc., in which fuel is stored; the reservoir cup 11 is arranged on the bottom of the fuel tank 10 to be continuously filled with fuel from the fuel tank 10; the fuel pump 13 pumps the fuel from the reservoir cup 11 to the engine, and discharges a portion of the fuel to the injection pump 12; the fuel filter 14 is arranged in the reservoir cup 11 to filter the fuel supplied to the engine; the injection pump 12 is arranged on the bottom of the reservoir cup 11, and fills the reservoir cup 11 with fuel by extracting fuel from the fuel tank 10.

[0006] In the fuel supply system of the related art, when the fuel is pumped from the fuel pump 13 to the engine due to the driving of the fuel pump 13 , a part of the fuel is discharged toward the jet pump 12 .

[0007] In addition, when the fuel discharged toward the jet pump 12 passes through the jet pump 12 , a vacuum suction force is instantaneously generated in the jet pump 12 .

[0008] Therefore, due to the instantaneous vacuum suction force of the jet pump 12 , the fuel is drawn from the fuel tank 10 into the reservoir cup 11 , thereby filling the reservoir cup 11 with the fuel.

[0009] In the accompanying drawings, Figure 2 is a conceptual diagram illustrating a fuel supply system according to another example of the related art.

[0010] refer to Figure 2The fuel supply system of the related art includes: a saddle-shaped fuel tank 10, a liquid storage cup 11, a fuel pump 13, a fuel filter 14, a first injection pump 12-1, a second injection pump 12-2, etc. The saddle-shaped fuel tank 10 includes a first fuel storage space 10-1 and a second fuel storage space 10-2 separated from the first fuel storage space 10-1; the liquid storage cup 11 is arranged at the bottom of the first fuel storage space 10-1 to be continuously filled with fuel from the fuel tank 10; the fuel pump 13 pumps the fuel from the liquid storage cup 11 to the second fuel storage space 10-2; is delivered to the engine, and a portion of the fuel is discharged to the first injection pump 12-1 and the second injection pump 12-2; the fuel filter 14 is arranged in the reservoir cup 11 to filter the fuel supplied to the engine; the first injection pump 12-1 is arranged at the bottom of the reservoir cup 11 to fill the reservoir cup 11 with fuel by drawing fuel from the first fuel storage space 10-1; the second injection pump 12-2 is installed inside the reservoir cup 11 to fill the reservoir cup 11 with fuel by drawing fuel from the second fuel storage space 10-2.

[0011] The fuel tank of the fuel supply system may be Figure 1 The integral fuel tank shown or Figure 2 Saddle-type fuel tank shown, depending on model.

[0012] In the fuel supply system including the saddle-shaped fuel tank, in addition to the first jet pump 12-1, a second jet pump 12-2 for pumping the fuel from the second fuel storage space 10-2 into the reservoir cup 11 by vacuum suction is also installed in the reservoir cup 11. Figure 2 shown.

[0013] In the related art fuel supply system, when fuel is pumped to the engine in response to the operation of the fuel pump 13, a portion of the fuel is discharged toward the first jet pump 12-1 and the second jet pump 12-2.

[0014] Referring to the internal configuration of each of the first jet pump 12-1 and the second jet pump 12-2, a nozzle 12-3 and a discharge pipe 12-4 through which the fuel discharged from the fuel pump 13 flows are provided on one side, as shown in FIG. Figure 2 On the other side, a fuel inlet 12-5 connected in a communicative manner to the second fuel storage space 10-2 of the fuel tank 10 and a fuel suction passage 12-6 extending in a communicative manner to the discharge pipe 12-4 are provided.

[0015] Therefore, when the fuel is pumped from the fuel pump 13 to the engine, when a portion of the fuel is quickly ejected through the nozzle 12-3 in the first injection pump 12-1 and the second injection pump 12-2 to refill the reservoir 11 through the discharge pipe 12-4, a vacuum suction force based on the injection pump principle is applied to the fuel suction channel 12-6 and the fuel inlet 12-5.

[0016] Subsequently, due to the vacuum suction force applied to the fuel suction channel 12-6 and the fuel inlet 12-5, fuel is drawn from the first fuel storage space 10-1 and the second fuel storage space 10-2 of the fuel tank through the fuel suction channel 12-6 and the fuel inlet 12-5, the fuel flows through the discharge pipe 12-4, and is then supplied to the liquid storage cup 11, thereby filling the liquid storage cup 11 with fuel.

[0017] As described above, in the saddle type fuel tank, due to the vacuum suction pumping of the first jet pump 12-1, the reservoir cup 11 can be easily filled with the fuel supplied from the first fuel storage space 10-1 of the fuel tank 10. In addition, due to the vacuum suction pumping of the second jet pump 12-2, the reservoir cup 11 can be easily filled with the fuel supplied from the second fuel storage space 10-2 of the fuel tank 10.

[0018] However, in the fuel supply system using the saddle type fuel tank, the second injection pump 12 - 2 used in addition to the first injection pump 12 - 1 may delay the time to increase the pressure of the fuel supplied to the engine in the cold start of the engine.

[0019] In other words, when fuel is pumped to the engine by the fuel pump during a cold start of the engine, a portion of the fuel discharged to the first and second injection pumps may cause flow loss, thereby increasing the time it takes for the fuel pressure supplied to the engine by the fuel pump to reach the set pressure for engine starting, thereby causing a delay in the cold start of the engine.

[0020] For example, although the time for the fuel pressure supplied to the engine by the fuel pump to increase to the set pressure in the cold start of the engine may take about 250 ms or less, the actual time for increasing the fuel pressure to the set pressure is more than 1 second. Figure 3 As a result, the cold starting capability of the engine may be reduced, which is problematic.

[0021] The above is only intended to help understand the background of the present invention, and is not intended to mean that the present invention falls within the scope of the relevant technologies known to those skilled in the art. Summary of the invention

[0022] The present invention has been made in view of the above problems arising in the related art, and the present invention aims to provide a valve system for a vehicle fuel pump, which is capable of reducing the time for the pressure of the fuel supplied by the fuel pump to the engine to increase to a set pressure when the engine is cold started, and ensuring that the injection pump is operable at any time after the engine is started.

[0023] In order to achieve the above objectives, according to one aspect of the present invention, a valve system for a vehicle fuel pump is provided, the valve system comprising: a reservoir cup, a fuel pump, an injection pump and an injection pump control valve, the reservoir cup being arranged in a fuel tank storing fuel therein; the fuel pump being configured to pump fuel from the reservoir cup to the engine and simultaneously supply fuel to the injection pump through a first discharge port; the injection pump being configured to fill the reservoir cup with fuel by drawing fuel from the fuel tank using the pressure of the fuel supplied by the fuel pump; and the injection pump control valve being arranged on the first discharge port to control the flow of fuel discharged from the fuel pump to the injection pump.

[0024] When the engine is started and the pressure of the fuel discharged from the fuel pump to the engine increases to reach a first set pressure, the injection pump control valve can connect the injection pump flow path connecting the injection pump and the first discharge port of the fuel pump, and when the engine is stopped and the pressure of the fuel discharged from the fuel pump to the injection pump decreases to reach a second set pressure determined to be less than the first set pressure, the injection pump control valve can close the injection pump flow path.

[0025] The injection pump control valve may include: a first valve housing, a plunger, a second valve housing, a piston, an elastic member and a foldable leaf spring, wherein the first valve housing has a plunger lifting path with a predetermined height arranged in the first valve housing, wherein the injection pump flow path is connected to the middle position of the plunger lifting path; the plunger is installed on the plunger lifting path in a liftable manner so as to connect and shut off the injection pump flow path according to the position on the plunger lifting path; the second valve housing has a piston lifting path with a predetermined height arranged in the second valve housing, and an opening is arranged on the first side wall portion of the second valve housing; the piston is installed on the piston lifting path in a liftable manner and is integrally connected to the plunger via a lifting rod; the elastic member is arranged between the bottom surface of the top end of the second valve housing and the top surface of the piston to be compressed when the plunger moves upward; the foldable leaf spring is installed on the top surface of the piston and is arranged between the piston and the elastic member so that the plunger moves upward due to the pressure of the fuel being equal to or greater than the first set pressure to connect the injection pump flow path.

[0026] The foldable leaf spring may include: a horizontal leaf spring portion, a vertical leaf spring portion and a folding leaf spring portion, the horizontal leaf spring portion being arranged in a piston lifting path to extend in a direction perpendicular to the direction of piston lifting and lowering, and an elastic member being arranged on the top surface of the horizontal leaf spring portion; the vertical leaf spring portion being attached to a first end of the horizontal leaf spring portion and being arranged in the piston lifting path along the direction of piston lifting and lowering, and the bottom end of the vertical leaf spring portion being fixedly mounted on the top surface of the piston; the folding leaf spring portion being integrally arranged at a second end portion of the horizontal leaf spring portion in a foldable manner, and being arranged in the piston lifting path to extend in the direction of piston lifting and lowering, and a flange being integrally arranged at the bottom end of the folding leaf spring portion to be inserted into the opening and supported by the opening.

[0027] When the folding leaf spring portion pivots about the second end of the horizontal leaf spring portion toward the bottom surface of the horizontal leaf spring portion due to the pressure of the fuel applied to the plunger by the fuel pump, the plunger can be released and separated from the opening and move upward in the plunger lifting path in the direction of connecting the injection pump flow path.

[0028] The foldable leaf spring may further include an inner spring disposed between the vertical leaf spring portion and the folding leaf spring portion, the inner spring configured to be compressed when the folding leaf spring portion pivots toward a bottom surface of the horizontal leaf spring portion.

[0029] The first set pressure may be a value obtained by adding a fuel pressure for compressively deforming the elastic member and a fuel pressure for foldingly deforming the foldable leaf spring.

[0030] The plunger lifting path may include an upper lifting path and a lower lifting path, the jet pump flow path being switched on when the plunger is in the upper lifting path and the jet pump flow path being switched off when the plunger is in the lower lifting path.

[0031] When the pressure of the fuel discharged to the injection pump at engine starting is equal to or greater than the first set pressure, the injection pump control valve can separate and release the flange of the foldable leaf spring from the opening, and the plunger is located in the upper lifting path to connect the injection pump flow path.

[0032] When the pressure of the fuel discharged to the injection pump when the engine is started is less than the first set pressure, the injection pump control valve can cause the flange of the foldable leaf spring to be located in the opening and supported by the opening, and the plunger to be located in the lower lifting path so that the injection pump flow path remains in the closed position.

[0033] In addition, when the pressure of the fuel discharged to the injection pump decreases to less than the first set pressure and greater than the second set pressure after the injection pump path is connected, the injection pump control valve can keep the flange of the foldable leaf spring released from the opening and keep the plunger in the upper lifting path so that the injection pump flow path remains in the connected position.

[0034] According to an embodiment of the present invention, the valve system of a vehicle fuel pump has a structure that can prevent flow loss of fuel flowing to an injection pump to reduce the time for the fuel pressure of the engine to increase, thereby improving the cold starting capability of the engine and ensuring that the operability of the injection pump is properly maintained after the engine is started. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects, features and other advantages of the present invention will be more clearly understood through the following detailed description in conjunction with the accompanying drawings, in which:

[0036] Figure 1 is a conceptual diagram showing a fuel supply system according to an example of the related art;

[0037] Figure 2 is a conceptual diagram showing a fuel supply system according to another example of the related art;

[0038] Figure 3 is a graph showing cold start capability of an engine associated with a related art fuel supply system;

[0039] Figure 4 is a configuration diagram showing a valve system of a fuel pump according to an embodiment of the present invention;

[0040] Figures 5 to 7 shows the operating state of the injection pump control valve according to an embodiment of the present invention;

[0041] Figure 8 : is a graph showing the results of evaluating the cold starting capability of the valve system of the present invention and the cold starting capability of the valve system of the related art. DETAILED DESCRIPTION

[0042] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

[0043] In the accompanying drawings, Figure 4 A vehicle fuel supply system in which the valve system of the fuel pump according to the embodiment of the present invention is used is shown.

[0044] refer to Figure 4The vehicle fuel supply system may include: a fuel tank 100, a reservoir cup 110, a fuel pump 130, a fuel filter 140, etc., wherein the fuel is stored in the fuel tank 100; the reservoir cup 110 is arranged on the bottom of the fuel tank 100 to continuously fill the reservoir cup 110 with the fuel from the fuel tank 100; the fuel pump 130 pumps the fuel from the reservoir cup 110 to the engine while supplying the fuel to the injection pump 120; the fuel filter 140 is arranged in the reservoir cup 110 to filter the fuel supplied to the engine.

[0045] The fuel tank 100 may be a saddle-type 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.

[0046] Where the fuel supply system includes a saddle-type fuel tank, such as Figure 4 As shown, the reservoir cup 110 is arranged at the bottom of the first fuel storage space 101 to continuously supply and fill it with fuel from the first fuel storage space 101. In addition, the first jet pump 121 is arranged on the bottom of the reservoir cup 110 to fill the reservoir cup 110 with fuel by drawing fuel from the first fuel storage space 101, and the second jet pump 122 is installed inside the reservoir cup 110 to fill the reservoir cup 110 with fuel from the second fuel storage space 102 by drawing fuel from the second fuel storage space 102.

[0047] In the fuel supply system, when the fuel discharged from the fuel pump 130 is pumped to the engine in response to driving the fuel pump 130 to drive the engine, the fuel is discharged toward the first jet pump 121 and the second jet pump 122. When the fuel discharged from the fuel pump 130 is supplied to the jet pump 120, the fuel can easily flow from the first fuel storage space 101 of the fuel tank 100 into the reservoir cup 110 in response to the vacuum suction pumping of the first jet pump 121, and the fuel can easily flow from the second fuel storage space 102 of the fuel tank 100 into the reservoir cup 110 in response to the vacuum suction pumping of the second jet pump 122.

[0048] The fuel pump 130 is provided with a first discharge port 131 for discharging the fuel from the reservoir cup 110 toward the injection pump 120 and a second discharge port 132 for discharging the fuel from the reservoir cup 110 toward the engine. When the fuel pump 130 pumps the fuel from the reservoir cup 110 to the engine through the second discharge port 132, the fuel pump 130 also supplies the fuel to the injection pump 120 through the first discharge port 131.

[0049] The first and second jet pumps 121 and 122 may fill the reservoir cup 110 with fuel by drawing fuel from the fuel tank 100 due to the pressure of the fuel supplied through the first discharge port 131 by the fuel pump 130 .

[0050] According to the present invention, the injection pump control valve 200 is installed on the first discharge port 131 of the fuel pump 130 .

[0051] The injection pump control valve 200 is configured to be able to control the flow of fuel discharged from the fuel pump 130 toward the injection pump 120 by opening and closing an injection pump flow path 214 connecting the injection pump 120 and the first discharge port 131 of the fuel pump 130 .

[0052] The injection pump control valve 200 may be operated in an on mode or an off mode according to the pressure of the fuel discharged by the fuel pump 130 through the first discharge port 131 .

[0053] like Figure 4 As shown, the injection pump control valve 200 is configured to open and close the injection pump flow path 214. When the engine is started and the pressure of the fuel discharged from the fuel pump 130 to the injection pump 120 increases to reach the first set pressure, the injection pump control valve 200 opens the injection pump flow path 214. When the engine is stopped and the pressure of the fuel discharged from the fuel pump 130 to the injection pump 120 decreases to reach the second set pressure, the injection pump control valve 200 closes the injection pump flow path 214.

[0054] That is, the injection pump control valve 200 is configured to maintain the injection pump flow path 214 in the closed position before the pressure of the fuel supplied by the fuel pump 130 to the engine and the injection pump 120 reaches the first set pressure.

[0055] In the operation of the fuel pump 130 , starting of the engine (particularly cold starting) may be facilitated only when the pressure of the fuel supplied to the engine by the fuel pump 130 reaches a set pressure.

[0056] In order to facilitate the starting of the engine, the first set pressure is determined as the fuel pressure value when the engine is started. For example, the first set pressure can be set within the range of 4.0 bar to 5.0 bar.

[0057] The second set pressure is determined as a fuel pressure value that switches the injection pump control valve 200 from the on mode to the off mode. That is, the second set pressure is a fuel pressure value that is determined to shut off the injection pump control valve 200 after the engine is started. The second set pressure is determined to be a value less than the first set pressure. Specifically, the set pressure can be set to a pressure value less than 2.5 bar.

[0058] In addition, the jet pump flow path 214 is a flow path connecting the inlet of the jet pump 120 and the first discharge port 131 of the fuel pump 130 .

[0059] The injection pump control valve 200 includes a first valve housing 210 and a second valve housing 220 as a framework to perform an on / off operation under the above conditions. A plunger lifting path 212 having a predetermined height is provided in the first valve housing 210, and a piston lifting path 222 having a predetermined height is provided in the second valve housing 220.

[0060] The first valve housing 210 allows the jet pump flow path 214 to be connected to a middle position of the plunger lifting path 212 , and the bottom of the first valve housing 210 is communicated with the first discharge port 131 of the fuel pump 130 .

[0061] The jet pump flow path 214 extends from the outside of the first valve housing 210 , and is connected to the plunger lifting path 212 via one end.

[0062] The plunger 230 is installed on the plunger lifting path 212 so that the plunger 230 can be lifted and lowered to open and close the jet pump flow path 214 .

[0063] The plunger 230 is configured to open and close the jet pump flow path 214 according to the position of the plunger lifting path 212. In this regard, the plunger 230 is arranged in the plunger lifting path 212 to divide the plunger lifting path 212 into two parts, namely, the upper lifting path 212a and the lower lifting path 212b.

[0064] When sliding upward to connect the jet pump flow path 214, the plunger 230 moves toward the upper lifting path 212a. When positioned in the upper lifting path 212a, the plunger 230 connects the jet pump flow path 214. In addition, when sliding downward to close the jet pump flow path 214, the plunger 230 moves toward the lower lifting path 212b. When positioned in the lower lifting path 212b, the plunger 230 closes the jet pump flow path 214.

[0065] That is, when the jet pump flow path 214 is turned on, the plunger 230 is located in the upper lifting path 212a. When the jet pump flow path 214 is turned off, the plunger 230 is located in the lower lifting path 212b.

[0066] In other words, at one side of the jet pump flow path 214, the plunger 230 has a first side portion 230a disposed within the plunger lifting path 212. The first side portion 230a shuts off or opens the jet pump flow path 214 according to a movement position.

[0067] The second valve housing 220 is disposed above the first valve housing 210 , and a piston lifting path 222 provided in the second valve housing 220 may be communicated with the plunger lifting path 212 of the first valve housing 210 .

[0068] The piston 240 is installed on the piston lifting path 222 so that the piston 240 can be lifted and lowered.

[0069] The piston 240 is configured so that it can slide up and down along the inner wall surface of the second valve housing 220 in the piston lifting path 222. The piston 240 is connected to the plunger 230 located in the plunger lifting path 212 via the lifting rod 242 so that the piston 240 and the plunger 230 move integrally.

[0070] When the piston 240 is located at the lowermost portion of the piston elevating path 222 , the plunger 230 is located at the uppermost portion of the lower elevating path 212 b to shut off the jet pump flow path 214 .

[0071] That is, when the piston 240 contacts the bottom surface of the second valve housing 220 , the plunger 230 is located at the highest position of the region in the plunger lifting path 212 that can shut off the jet pump flow path 214 .

[0072] In other words, when the plunger 230 moves downward because the pressure of the fuel discharged from the first discharge port 131 of the fuel pump 130 is equal to or less than the second set pressure, the bottom surface of the second valve housing 220 can limit the downward movement distance of the piston 240, so that the plunger 230 can reliably close the injection pump flow path 214 and prevent the plunger 230 from moving further downward to connect the injection pump flow path 214.

[0073] In addition, the elastic member 250 and the foldable leaf spring 260 are installed on the piston ascending and descending path 222 between the bottom surface 220 b of the top end of the second valve housing 220 and the top surface 240 a of the piston 240 .

[0074] The elastic member 250 may be elastically compressed by the pressure of the fuel supplied to the bottom of the plunger 230 by the fuel pump 130. The elastic member 250 is arranged in the piston lifting path 222 so that the elastic member 250 can be compressed or restored in the lifting direction of the piston 240 (i.e., the direction in which the piston 240 is lifted and lowered).

[0075] Specifically, the elastic member 250 is installed between the bottom surface 220 b of the top end of the second valve housing 220 and the top end of the foldable leaf spring 260 so that the elastic member 250 is compressed during the upward movement of the piston 240 and restored during the downward movement of the piston 240 .

[0076] In addition, between the piston 240 and the elastic member 250, a foldable leaf spring 260 is installed on the top surface of the piston 240. The foldable leaf spring 260 is configured to inhibit the jet pump flow path 214 from being opened by the fuel pressure less than the first set pressure.

[0077] In other words, when the pressure of the fuel applied to the plunger 230 is less than the first set pressure and greater than the second set pressure, the foldable leaf spring 260 inhibits the plunger 230 from moving upward in the plunger lifting path 212 and inhibits the injection pump flow path 214 from being connected.

[0078] In this regard, the foldable leaf spring 260 includes a vertical leaf spring portion 262, a horizontal leaf spring portion 264, and a folded leaf spring portion 266, each of which is implemented as an elastic leaf spring member.

[0079] The vertical leaf spring portion 262 is arranged in the piston lifting path 222 to extend in the lifting direction of the piston 240 and is arranged below the elastic member 250 , and the bottom end of the vertical leaf spring portion 262 is fixedly mounted on the top surface 240 a of the piston 240 .

[0080] The top end of the vertical leaf spring portion 262 is fixedly attached to the first end portion 264 a of the horizontal leaf spring portion 264 .

[0081] The horizontal leaf spring portion 264 is disposed in the piston ascending and descending path 222 to extend in a direction perpendicular to the ascending and descending direction of the piston 240 , ie, a horizontal direction, and the elastic member 250 is disposed on a top surface of the horizontal leaf spring portion 264 .

[0082] In addition, the folding leaf spring portion 266 is arranged in the piston ascending and descending path 222 to extend in the ascending and descending direction of the piston 240 , and is integrally provided on the second end portion 264 b of the horizontal leaf spring portion 264 in a foldable manner.

[0083] In other words, the folded leaf spring portion 266 integrally extends from the second end portion 264 b of the horizontal leaf spring portion 264 to be arranged perpendicular to the horizontal leaf spring portion 264 .

[0084] When the plunger 230 moves upward, the folded leaf spring portion 266 connects the injection pump flow path 214 while being folded toward the horizontal leaf spring portion 264. Here, the top end of the folded leaf spring portion 266 integrally connected to the second end 264b of the horizontal leaf spring portion 264 may be a bent portion of the foldable leaf spring 260.

[0085] In other words, when the pressure of the fuel applied to the plunger 230 reaches the first set pressure, the folded 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.

[0086] The folding leaf spring portion 266 has a flange 266a integrally provided at its bottom end. The flange 266a is inserted into and supported by the opening 224 of the second valve housing 220. The opening 224 is provided on the first side wall portion 220a of the second valve housing 220 to be arranged at a middle position between the first side wall portion 220a and the piston lifting path 222.

[0087] Despite Figure 4 The center flange 266 a is shown as being disposed perpendicularly to the folded leaf spring portion 266 , but when the shape of the opening 224 is changed, the flange 266 a may be disposed at an obtuse angle relative to the folded leaf spring portion 266 .

[0088] The flange 266a is provided to extend from the bottom end of the folded leaf spring portion 266 in a direction opposite to the vertical leaf spring portion 262. The flange 266a remains supported by the opening 224 until the fuel pressure applied to the plunger 230 reaches a first set pressure.

[0089] When the folding leaf spring portion 266 is folded by pivoting about the second end portion 264 b of the horizontal leaf spring portion 264 toward the bottom surface of the horizontal leaf spring portion 264 , the flange 266 a is released from the opening 224 .

[0090] When the flange 266a is separated and released from the opening 224, the foldable leaf spring 260 causes the plunger 230 to move upward.

[0091] Even in a case where the fuel pressure applied to the bottom surface of the plunger 230 is greater than the fuel pressure for compressing and deforming the elastic member 250 (i.e., the first fuel pressure), when the fuel pressure applied to the bottom surface of the plunger 230 is less than the sum (i.e., the third fuel pressure) obtained by adding the first fuel pressure and the fuel pressure for folding the foldable leaf spring 260 (i.e., the second fuel pressure), the foldable leaf spring 260 having the above-mentioned construction suppresses the upward movement of the plunger 230 for connecting the injection pump flow path 214.

[0092] The third fuel pressure is a value obtained by adding the first fuel pressure for compressing and deforming the elastic member 250 and the second fuel pressure for folding and deforming the foldable leaf spring 260. The third fuel pressure is set to a minimum pressure value of the fuel applied to the plunger 230 by the fuel pump 130 for the on-operation of the injection pump control valve 200.

[0093] The third fuel pressure may be determined to be a value equal to or greater than an engine starting reference fuel pressure (ie, the first set pressure) supplied to the engine through the fuel pump 130 .

[0094] For example, the minimum fuel pressure value applied to plunger 230 by fuel pump 130 for the on operation of injection pump control valve 200 may be set within the range of 4.5±0.5 bar. The maximum fuel pressure value for the off operation of injection pump control valve 200 may be set within the range of 2.0±0.5 bar.

[0095] In addition, the foldable leaf spring 260 may further include an inner spring 268 disposed between the vertical leaf spring portion 262 and the foldable leaf spring portion 266 .

[0096] The inner spring 268 is configured to press the folded leaf spring portion 266 toward the first side wall portion 220a of the second valve housing 220 in the piston ascending and descending path 222. When the folded leaf spring portion 266 is folded toward the horizontal leaf spring portion 264, the inner spring 268 is elastically compressed.

[0097] Additionally, the internal spring 268 may help restore the shape of the accordion leaf spring 260 and help restore the position of the accordion leaf spring portion 266 when the plunger 230 moves downward to close the inlet to the injection pump flow path 214 .

[0098] When the plunger 230 moves downward to a position closing the inlet of the injection pump flow path 214, the folded leaf spring portion 266 can return toward the first side wall portion 220a of the second valve housing 220 due to its elasticity, while restoring the flange 266a to the opening 224. With the help of the internal spring 268, the folded leaf spring portion 266 can more easily return toward the first side wall portion 220a while restoring the flange 266a to the opening 224.

[0099] Here, we will refer to Figures 5 to 7 The operating state of the fuel system of the vehicle pumping valve having the above-mentioned configuration will be described.

[0100] Figures 5 to 7 The operating state of the injection pump control valve according to the present invention is shown. Figure 5 shows the valve operation state before the pressure of the fuel supplied to the engine by the fuel pump reaches the first set pressure at the time of engine startup, Figure 6 shows the valve operation state after the pressure of the fuel supplied to the engine by the fuel pump reaches the first set pressure at the time of engine startup, Figure 7 The valve operation state is shown after the pressure of the fuel supplied to the engine by the fuel pump has reached the second set pressure when the engine is stopped.

[0101] like Figure 5As shown, even when the pressure of the fuel discharged from the fuel pump 130 is applied to the plunger 230 when the engine is started, when the pressure of the fuel applied to the plunger 230 is less than the first set pressure for connecting the injection pump flow path 214, the plunger 230 maintains the injection pump flow path 214 in the closed position.

[0102] Accordingly, fuel supply to the jet pump 120 is prevented until the pressure of the fuel supplied to the engine 300 reaches the first set pressure for proper starting of the engine 300, and only the fuel line connecting the fuel pump 130 and the engine 300 is connected to supply the fuel from the reservoir cup 110 to the engine 300. Therefore, the flow loss of the fuel flowing to the jet pump 120 is prevented, thereby reducing the time when the fuel pressure increases during the engine starting.

[0103] Thereafter, when the pressure of the fuel discharged from the fuel pump 130 to the engine 300 increases to reach the first set pressure, the pressure of the fuel discharged from the fuel pump 130 to be supplied to the plunger 230 also reaches the first set pressure.

[0104] like Figure 6 As shown, when the pressure of the 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 separated from the opening 224 of the second valve housing 220, so that the plunger 230 moves upward. Since the plunger 230 moves upward while compressing the elastic member 250, the injection pump flow path 214 is connected.

[0105] refer to Figure 8 Compared with the case of the related art in which the time taken to increase the pressure of the fuel supplied by the fuel pump to the engine to the first set pressure in the cold start of the engine is about 1 second, the present invention can reduce the time to about 250ms. Therefore, even in the cold start, the engine can be started quickly and easily, thereby improving the cold start capability of the engine.

[0106] In addition, after the jet pump flow path 214 is turned on, when the pressure of the fuel supplied to the jet pump 120 is less than the first set pressure and greater than the second set pressure, the compressed state of the elastic member 250 is maintained by the fuel pressure exceeding the second set pressure (i.e., the pressure for compressing and deforming the elastic member) because the flange 266a of the foldable leaf spring 260 has been released from the opening 224. Therefore, the plunger 230 is continuously located in the upper lifting path 212, so that the jet pump flow path 214 is maintained in the turned-on position.

[0107] In other words, after jet pump flow path 214 is turned on, when the pressure of the fuel applied to plunger 230 is greater than the second set pressure, the compressed state of elastic member 250 is maintained, and thus, the turned-on position of jet pump flow path 214 can be maintained.

[0108] In addition, since the operation of the fuel pump 130 stops when the engine stops, the pressure of the fuel applied to the plunger 230 is reduced to reach the second set pressure, and the plunger 230 moves downward due to the restoring force of the elastic member 250 to close the injection pump flow path 214, as shown in FIG. Figure 7 shown.

[0109] Although the embodiments of the present invention 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 invention as disclosed in the accompanying claims.

Claims

1. A valve system for a vehicle fuel pump, the valve system comprising: a liquid storage cup disposed in the fuel tank storing fuel in the liquid storage cup; a fuel pump configured to pump fuel from the reservoir cup to the engine while supplying fuel to the injection pump through the first discharge port; an injection pump configured to fill the reservoir cup with fuel by drawing fuel from a fuel tank using the pressure of the fuel supplied by the fuel pump; as well as an injection pump control valve disposed on the first discharge port and configured to control the flow of fuel discharged from the fuel pump to the injection pump, wherein, when the engine is turned on and the pressure of the fuel discharged from the fuel pump to the engine increases to reach a first set pressure, the injection pump control valve connects the injection pump flow path connecting the injection pump and the first discharge port of the fuel pump; When the engine is turned off and the pressure of the fuel discharged from the fuel pump to the injection pump decreases to reach a second set pressure determined to be less than the first set pressure, the injection pump control valve shuts off the injection pump flow path, Wherein, the jet pump control valve comprises: a first valve housing in which a plunger lifting 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 lifting path; a plunger which is arranged on the plunger lifting path in a manner that allows it to be lifted and lowered so as to open and close the injection pump flow path according to a position of the plunger on the plunger lifting path; a second valve housing defining a piston elevation path having a predetermined height therein, and the second valve housing having an opening defined on a first side wall portion of the second valve housing; a piston which is arranged on the piston lifting path in a manner capable of being lifted and lowered and is configured to be integrally connected to the plunger via a lifting rod; an elastic member disposed between a bottom surface of a top end of the second valve housing and a top surface of the piston, the elastic member being configured to be compressed when the plunger moves upward; and A foldable leaf spring is arranged on a top surface of the piston and between the piston and the elastic member so that the plunger is configured to move upward due to a pressure of the fuel being equal to or greater than a first set pressure to open the injection pump flow path.

2. The valve system of a vehicle fuel pump according to claim 1, wherein: The foldable leaf spring comprises: a horizontal leaf spring portion arranged in the piston lifting and lowering path to extend in a direction perpendicular to a direction in which the piston is lifted and lowered, the elastic member being arranged 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 arranged in a piston lifting and lowering path along a direction in which the piston is lifted and lowered, a bottom end of the vertical leaf spring portion being fixedly arranged on a top surface of the piston; and A foldable leaf spring portion is configured to be integrally arranged at the second end of the horizontal leaf spring portion in a foldable manner and arranged in the piston lifting path to extend in the direction of piston lifting and lowering, and a flange is integrally arranged at the bottom end of the foldable leaf spring portion to extend through the opening and be supported by the opening.

3. The valve system of a vehicle fuel pump according to claim 2, wherein: When the folding leaf spring portion pivots about the second end of the horizontal leaf spring portion toward the bottom surface of the horizontal leaf spring portion due to the pressure of the fuel applied to the plunger by the fuel pump, the flange is released and separated from the opening, and the plunger is configured to move upward in the plunger lifting path in the direction of connecting the injection pump flow path.

4. The valve system of a vehicle fuel pump according to claim 2, wherein: The foldable leaf spring further includes an inner spring disposed between the vertical leaf spring portion and the folding leaf spring portion, the inner spring configured to be compressed when the folding leaf spring portion pivots toward a bottom surface of the horizontal leaf spring portion.

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

6. The valve system of a vehicle fuel pump according to claim 2, wherein: The plunger lifting path includes: an upper lifting path, wherein the plunger is located in the upper lifting path to connect to the jet pump flow path; and The plunger blocks the jet pump flow path when the plunger is located in the lower lifting path.

7. The valve system of a vehicle fuel pump according to claim 6, wherein: When the pressure of the fuel discharged to the injection pump at engine starting is equal to or greater than a first set pressure, the injection pump control valve causes the flange of the foldable leaf spring to separate and release from the opening, and the plunger is located in the upper lifting path to connect the injection pump flow path.

8. The valve system of a vehicle fuel pump according to claim 6, wherein: When the pressure of the fuel discharged to the injection pump is less than the first set pressure when the engine is started, the injection pump control valve causes the flange of the foldable leaf spring to be located in the opening and supported by the opening, and the plunger to be located in the lower lifting path so that the injection pump flow path is maintained in the closed position.

9. The valve system of a vehicle fuel pump according to claim 6, wherein: When the pressure of the fuel discharged to the injection pump decreases to be less than the first set pressure and greater than the second set pressure after the injection pump path is connected, the injection pump control valve keeps the flange of the foldable leaf spring released from the opening and keeps the plunger in the upper lifting path so that the injection pump flow path is maintained in the connected position.

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