Valve system for a fuel pump of a vehicle

Abstract

The present invention relates to a valve system for a fuel pump of a vehicle. The valve system for a fuel system of a vehicle can close an injection pump side flow path when the pressure of fuel supplied from a fuel pump to an engine is lower than a prescribed fuel pressure at engine startup, and open the injection pump side flow path when the fuel pressure is equal to or higher than the prescribed fuel pressure at engine startup, thereby improving the cold start performance of the engine, and can also allow the injection pump side flow path to remain in an open state between a low load region and a high load region of the engine after the engine is started, thereby smoothly maintaining the function of the injection pump after the engine is started.

Description

Technical Field

[0001] The present disclosure relates to a valve system of a fuel pump for a vehicle, and more particularly, to a valve system of a fuel pump for improving cold start performance of an engine. Background Art

[0002] Generally, a fuel supply system of a vehicle is a system for smoothly supplying fuel required by an engine under all driving conditions, and is one of the factors having a great influence on the output power or performance of the engine.

[0003] In recent years, in order to improve the output power and performance of the engine under various driving conditions, a jet pump system is used to smoothly fill the fuel into the reservoir of the fuel tank even under the condition of maximum fuel consumption of the engine.

[0004] Figure 1 is a schematic diagram showing a fuel supply system according to an example of the related art.

[0005] refer to Figure 1 The fuel supply system is configured to include a single type fuel tank 10 for storing fuel, an oil cup 11 installed on the bottom side of the fuel tank 10 to be continuously filled with fuel in the fuel tank, a fuel pump 13 for pumping the fuel in the oil cup 11 to the engine and discharging some of the fuel to an injection pump 12, a fuel filter 14 installed in the oil cup 11 to filter the fuel supplied to the engine, an injection pump 12 installed on the bottom side of the oil cup 11 to suck the fuel in the fuel tank into the oil cup 11 and fill the oil cup, etc.

[0006] In the fuel supply system according to the conventional example, when the fuel is pumped from the fuel pump 13 to the engine by driving the fuel pump 13 , some of the fuel is discharged toward the injection pump 12 .

[0007] Then, when the fuel discharged toward the injection pump 12 passes through the injection pump 12 , vacuum suction force is generated in the injection pump 12 instantaneously.

[0008] Therefore, the fuel present in the fuel tank 10 is sucked by the instantaneous vacuum suction force of the jet pump 12 and filled into the fuel reservoir 11 .

[0009] Figure 2 is a schematic diagram showing a fuel supply system according to another example of the related art.

[0010] refer to Figure 2, the fuel supply system is configured to include: a saddle-shaped fuel tank 10, which is divided into a first fuel storage space 10-1 and a second fuel storage space 10-2; an oil cup 11, which is installed on the bottom side of the first fuel storage space 10-1 of the fuel tank 10 to be continuously filled with fuel in the fuel tank; a fuel pump 13, which is used to pump the fuel in the oil cup 11 to the engine and discharge some of the fuel to the first injection pump 12-1 and the second injection pump 12-2; a fuel filter 14 installed inside the oil cup 11 to filter the fuel to be supplied to the engine; a first injection pump 12-1 installed on the bottom side of the oil cup 11 to suck the fuel in the first fuel storage space 10-1 of the fuel tank into the oil cup 11 and fill the oil cup with fuel; a second injection pump 12-2 installed at a predetermined position in the oil cup 11 to suck the fuel in the second fuel storage space 10-2 of the fuel tank into the oil cup 11 and fill the oil cup with fuel, etc.

[0011] According to the vehicle model, such as Figure 1 As shown, a single type of oil tank may be used as the fuel tank 10, or as Figure 2 As shown, a saddle-type fuel tank divided into a first fuel storage space 10 - 1 and a second fuel storage space 10 - 2 may also be used.

[0012] If a saddle type fuel tank is used as the fuel tank 10, then Figure 2 As shown, in addition to the first jet pump 12-1 installed on the bottom side of the oil cup 11 to vacuum-suck the fuel in the first fuel storage space 10-1 of the fuel tank into the oil cup 11 and fill the oil cup with fuel, a second jet pump 12-2 for vacuum-sucking the fuel in the second fuel storage space 10-2 into the oil cup 11 is installed in the oil cup 11.

[0013] In the aforementioned fuel supply system according to another example of the related art, when the fuel is pumped from the fuel pump 13 to the engine by driving the fuel pump 13, some of the fuel is discharged toward the first jet pump 12-1 and the second jet pump 12-2.

[0014] At this time, if Figure 2 As shown, reviewing the internal configuration 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 fuel is discharged from the fuel pump 13 are formed in a line on one side, and a fuel inlet 12-5 connected to communicate with the second fuel storage space 10-2 of the fuel tank 10 and a fuel suction path 12-6 extending to communicate with the discharge pipe 12-4 are formed on the other side.

[0015] Therefore, when the fuel is pumped from the fuel pump 13 to the engine, if some of the fuel is quickly injected through the nozzles 12-3 in the first injection pump 12-1 and the second injection pump 12-2 and thus refilled into the oil storage cup 11 through the discharge pipe 12-4, the vacuum suction force generated according to the principle of the injection pump acts on the fuel suction path 12-6 and the fuel inlet 12-5.

[0016] Subsequently, the fuel existing in the first fuel storage space 10-1 and the second fuel storage space 10-2 of the fuel tank 10 is sucked through the fuel inlet 12-5 and the fuel suction path 12-6 by the vacuum suction force acting on the fuel suction path 12-6 and the fuel inlet 12-5, and then passes through the discharge pipe 12-4 to be filled into the oil storage cup 11.

[0017] As described above, in the saddle type fuel tank, the fuel existing in the first fuel storage space 10-1 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the first jet pump 12-1, and the fuel existing in the second fuel storage space 10-2 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the second jet pump 12-2.

[0018] However, when a saddle type fuel tank is adopted as the fuel tank 10, since the first jet pump 12-1 and the second jet pump 12-2 are used, there is a problem of a time delay required to increase the pressure of the fuel supplied to the engine when the engine is cold started.

[0019] That is, when fuel is pumped from the fuel pump to the engine at the time of a cold start of the engine, some of the fuel discharged to the first injection pump and the second injection pump acts as a flow loss, and thus there is a problem in that a long time is required for the fuel pressure supplied from the fuel pump to the engine to increase to the prescribed fuel pressure required for starting, which results in a problem of poor cold start performance, which prevents the engine from starting smoothly in winter.

[0020] For example, when the engine is cold started, the time required to increase the pressure of the fuel supplied from the fuel pump to the engine to the prescribed fuel pressure is preferably about 250 ms or less, but if Figure 3 As shown, the time required to increase the fuel pressure to the specified fuel pressure is delayed by about 1 second or longer, which causes a problem in that the cold startability of the engine is deteriorated.

[0021] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. Summary of the invention

[0022] The present disclosure provides a valve system for a fuel system of a vehicle, which can close a jet pump-side flow path when the pressure of fuel supplied from a fuel pump to an engine is lower than a specified fuel pressure when the engine is started, and open the jet pump-side flow path when the fuel pressure is equal to or higher than the specified fuel pressure when the engine is started, thereby improving the cold start performance of the engine, and can also allow the jet pump-side flow path to remain open between a low load area and a high load area of ​​the engine after starting, thereby smoothly maintaining the function of the jet pump after the engine is started.

[0023] To achieve the objective, the present disclosure provides a valve system for a fuel pump of a vehicle, which may include an oil storage cup installed in a fuel tank; an injection pump for filling the oil storage cup with fuel in the fuel tank; the fuel pump, on which a first discharge port for discharging the fuel in the oil storage cup to an engine and a second discharge port for discharging some of the fuel discharged to the engine to the injection pump are formed; and an injection pump control valve installed on the second discharge port of the fuel pump, wherein the injection pump control valve is configured to close an injection pump side flow path toward the injection pump when the pressure of the fuel supplied from the fuel pump to the engine is lower than a prescribed fuel pressure at engine startup, open the injection pump side flow path toward the injection pump when the fuel pressure is equal to or higher than the prescribed fuel pressure at engine startup, and after startup, keep the injection pump side flow path in an open state even between a low load region and a high load region of the engine.

[0024] An injection pump control valve according to a preferred exemplary embodiment of the present disclosure is composed of: a first valve body having a plunger (plunger, piston) ascending / descending path with a predetermined height formed therein, and having an injection pump side flow path toward the injection pump formed at a middle position of the plunger ascending / descending path; a second valve body provided in a structure in which a friction path is formed and formed at an upper portion of the first valve body to communicate with the first valve body; a plunger located in the plunger ascending / descending path to ascend / descend; a valve head positioned to frictionally contact the friction path and ascend / descend; an ascending / descending rod connected between the plunger and the valve head; and a spring connected between an upper end of the second valve body and an upper surface of the plunger to be compressed.

[0025] The plunger rising / falling path consists of an upper rising / falling path in which the plunger is located to allow the injection pump side flow path to be opened and a lower rising / falling path in which the plunger is located to allow the injection pump side flow path to be closed.

[0026] The valve head is formed as a spherical structure which is in frictional contact with the inner surface of the friction path.

[0027] The friction path may have locking protrusions formed at upper and lower ends thereof, the locking protrusions limiting a rising / falling distance of the valve head.

[0028] In particular, the total pressure obtained by adding a first pressure acting on the plunger to allow the valve head to frictionally rise / fall from the lower part to the upper part of the friction path and a second pressure used to compress the spring when the plunger and the valve head rise is set to be equal to or higher than the prescribed fuel pressure at the time of engine starting, and fuel is supplied from the fuel pump to the engine at the time of engine starting.

[0029] Therefore, when the fuel pressure supplied from the fuel pump to the engine is lower than the specified fuel pressure at engine start-up, the valve head is located at the lower part of the friction path, and the plunger is located in the lower rising / falling path of the plunger rising / falling path to keep the injection pump side flow path closed.

[0030] In addition, when the pressure of the fuel supplied from the fuel pump to the engine is equal to or higher than the specified fuel pressure when the engine is started, the plunger rises to the upper rising / falling path of the plunger rising / falling path, and the valve head rises to the upper part of the friction path while compressing the spring to allow the injection pump side flow path to open.

[0031] In addition, even if the pressure of the fuel supplied from the fuel pump to the engine drops to below the specified fuel pressure at engine start in the low load area and the intermediate load area of ​​the engine after the engine is started, when the fuel pressure is equal to or higher than the second pressure for compressing the spring, the plunger is continuously located in the upper rising / falling path of the plunger rising / falling path, and the valve head is also continuously located in the upper part of the friction path to keep the injection pump side flow path continuously in an open state.

[0032] Preferably, a cover having a spring connected to a bottom surface thereof is detachably mounted to an upper end of the second valve body.

[0033] Through the above configuration, the present disclosure provides the following effects.

[0034] Firstly, by closing the injection pump side flow path until the pressure of the fuel supplied from the fuel pump to the engine reaches the specified fuel pressure when the engine is started, the loss of fuel discharged to the injection pump when the engine is cold started can be eliminated, thereby shortening the time required for the pressure of the fuel supplied from the fuel pump to the engine to increase to the specified fuel pressure when the engine is cold started, thereby improving the cold start performance of the engine.

[0035] Secondly, by opening the injection pump side flow path after the engine is started, and then keeping the injection pump side flow path open even between the low load area and the high load area of ​​the engine, the function of the injection pump itself, that is, filling the oil storage cup with fuel in the fuel tank after the engine is started, can be smoothly maintained.

[0036] Other aspects and preferred embodiments of the disclosure are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other features of the present disclosure will now be described in detail with reference to certain exemplary embodiments thereof shown in the accompanying drawings, which are given below by way of illustration only and thus do not limit the present disclosure, and in which:

[0038] Figure 1 is a schematic diagram showing a fuel supply system according to an example of the related art.

[0039] Figure 2 is a schematic diagram showing a fuel supply system according to another example of the related art.

[0040] Figure 3 is a graph showing evaluation results of cold start performance of an engine for a conventional fuel supply system of the related art.

[0041] Figure 4 is a partially enlarged cross-sectional view showing a valve system of a fuel pump for a vehicle according to the present disclosure.

[0042] Figures 5 to 7 is a cross-sectional view showing an operating state of a valve system of a fuel pump for a vehicle according to the present disclosure.

[0043] Figure 8 is a graph showing evaluation results of cold start performance of an engine of a valve system for a fuel pump for a vehicle according to the present disclosure, wherein the time to reach a prescribed pressure of 5 bar in the present disclosure is 250 ms, while the time to reach a prescribed pressure of 5 bar in the related art is 1 s.

[0044] It should be understood that the accompanying drawings are not necessarily drawn to scale, presenting a somewhat simplified representation of various preferred features illustrating the basic principles of the present disclosure. The specific design features of the present disclosure disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the specific intended application and use environment.

[0045] In the drawings, reference numbers refer to the same or equivalent parts of the present disclosure throughout the several figures of the drawing. DETAILED DESCRIPTION

[0046] It should be understood that the term "vehicle" or "vehicular" or other similar terms used herein include motor vehicles, generally passenger vehicles including, for example, sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft including various ships, aircraft, etc., and include hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuel derived from non-petroleum resources). As referred to herein, a hybrid vehicle is a vehicle having two or more power sources, such as a gasoline-powered vehicle and an electric vehicle.

[0047] The terms used herein are only used for the purpose of describing specific embodiments, and are not intended to limit the present disclosure. As used herein, the singular forms "one", "a kind of" and "the" are intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include" and / or "comprise" specify the presence of the features, integers, steps, operations, elements and / components when used in this specification, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their combinations. As used herein, the term "and / or" includes any and all combinations of one or more related listed items. Throughout the specification, unless there is a clear description to the contrary, the word "include" and variants such as "include" or "contain" will be understood to imply the inclusion of the elements, but do not exclude any other elements. In addition, the terms "unit", "-piece", "-device" and "module" described in the specification refer to units for processing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0048] In addition, the control logic of the present disclosure may be implemented as a non-transitory computer-readable medium on a computer-readable medium containing executable program instructions executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, compact disk (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium may also be distributed in a computer system coupled to a network so that the computer-readable medium is stored and executed in a distributed manner, for example, by a telematics server or a controller area network (CAN).

[0049] Hereinafter, reference will now be made in detail to various exemplary embodiments of the present disclosure, examples of which are shown in the accompanying drawings and described below. Although the present disclosure will be described in conjunction with the exemplary embodiments, it should be understood that this description is not intended to limit the present disclosure to those exemplary embodiments. On the contrary, the present disclosure is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments that may be included within the spirit and scope of the present disclosure as defined by the appended claims.

[0050] Hereinafter, preferred exemplary embodiments of the present disclosure are described in detail with reference to the accompanying drawings.

[0051] Figure 4 A valve system for a fuel pump of a vehicle according to the present disclosure is shown.

[0052] like Figure 4 As shown, the valve system for a vehicle can be configured to include: a saddle-shaped fuel tank 10, which is divided into a first fuel storage space 10-1 and a second fuel storage space 10-2; an oil cup 11, which is installed on the bottom side of the first fuel storage space 10-1 of the fuel tank 10 to be continuously filled with fuel in the fuel tank; a fuel pump 13, which is used to pump the fuel in the oil cup 11 to the engine and discharge some of the fuel to the first injection pump 12-1 and the second injection pump 12-2; a fuel filter 14 installed inside the oil cup 11 to filter the fuel supplied to the engine; a first injection pump 12-1 installed on the bottom side of the oil cup 11 to suck the fuel in the first fuel storage space 10-1 of the fuel tank into the oil cup 11 and fill the oil cup with fuel; and a second injection pump 12-2 installed at a predetermined position in the oil cup 11 to suck the fuel in the second fuel storage space 10-2 of the fuel tank into the oil cup 11 and fill the oil cup with fuel.

[0053] If a saddle type fuel tank is used as the fuel tank 10, then Figure 2 As shown, in addition to installing a first jet pump 12-1 on the bottom side of the oil cup 11 to vacuum-absorb the fuel in the first fuel storage space 10-1 of the fuel tank into the oil cup 11 and fill the oil cup with fuel, a second jet pump 12-1 for vacuum-absorbing the fuel in the second fuel storage space 10-2 into the oil cup 11 is installed in the oil cup 11.

[0054] At this time, a first discharge port 13 - 1 for supplying the fuel in the oil cup 11 to the engine and a second discharge port 13 - 2 for discharging some of the fuel supplied to the engine to the first and second jet pumps 12 - 1 and 12 - 2 are formed on the fuel pump 13 .

[0055] Therefore, when the fuel pump 13 is driven, if the fuel is discharged from the first discharge port 13-1 and pumped to the engine, some of the fuel is discharged through the second discharge port 13-2 and flows to the first injection pump 12-1 and the second injection pump 12-2, so that the fuel existing in the first fuel storage space 10-1 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the first injection pump 12-1, and the fuel existing in the second fuel storage space 10-2 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the second injection pump 12-2.

[0056] According to the present disclosure, the injection pump control valve 100 is mounted on the second discharge port 13 - 2 of the fuel pump 13 .

[0057] The jet pump control valve 100 is configured to close the jet pump side flow path toward the first jet pump 12 - 1 and the second jet pump 12 - 2 when the pressure of the fuel supplied from the fuel pump 13 to the engine is lower than a prescribed fuel pressure at engine startup.

[0058] In addition, the injection pump control valve 100 is configured to open the injection pump side flow path toward the first injection pump 12-1 and the second injection pump 12-2 when the fuel pressure is equal to or higher than the prescribed fuel pressure when the engine is started, and to keep the injection pump side flow path open even between a low load area where the fuel pressure may drop below the prescribed fuel pressure after the engine is started and a high load area of ​​the engine.

[0059] To this end, the injection pump control valve 100 is configured to include a first valve body 110, which has a plunger rising / descending path 112 with a predetermined height formed therein, and has an injection pump side flow path 114 formed at a middle position of the plunger rising / descending path 112 toward the first injection pump 12-1 and the second injection pump 12-2; and a second valve body 120, which is arranged to have a structure in which a friction path 122 is formed, and is connected to the upper portion of the first valve body 110 to communicate with the first valve body.

[0060] In addition, the plunger 130 is located in the plunger ascending / descending path 112 of the first valve body 110 to ascend / descend.

[0061] Preferably, the plunger rising / descending path 112 consists of an upper rising / descending path 112-1 and a lower rising / descending path 112-2, and the plunger 130 is located in the upper rising / descending path 112-1 to allow the injection pump side flow path 114 to be opened, and the plunger 130 is located in the lower rising / descending path 112-2 to allow the injection pump side flow path 114 to be closed.

[0062] That is, the plunger rising / descending path 112 has an upper rising / descending path 112-1 and a lower rising / descending path 112-2, the plunger 130 is located in the upper rising / descending path 112-1 to allow the jet pump side flow path 114 to be opened in its upper space, and the plunger 130 is located in the lower rising / descending path 112-2 to allow the jet pump side flow path 114 to be closed in its lower space relative to the jet pump side flow path 114.

[0063] In addition, the valve head 134 is located on the friction path 122 of the second valve body 120 to be in friction contact therewith and to rise / fall.

[0064] Preferably, the valve head 134 may be formed in a spherical structure that frictionally contacts the inner surface of the friction path 122 , and further, may be formed in other shapes that may frictionally contact the inner surface of the friction path 122 .

[0065] In order to limit the vertical ascending / descending distance of the valve head 134 , locking protrusions 124 are formed to protrude from inner wall positions of upper and lower ends of the friction path 122 , respectively, and the upper and lower ends of the valve head 134 are locked to the locking protrusions 124 , respectively.

[0066] At this time, the ascending / descending rod 132 is connected between the upper surface of the plunger 130 and the lower surface of the valve head 134 so that the plunger 130 and the valve head 134 perform ascending / descending motion together.

[0067] In addition, the spring 140 is connected between the upper end of the second valve body 120 and the upper surface of the plunger 130 to be compressed.

[0068] Preferably, by detachably mounting the cover 126 on the upper end of the second valve body 120 and connecting the spring 140 to the lower surface of the cover, the spring 140 can be easily embedded in the interior of the second valve body 120 .

[0069] According to the present disclosure, the total pressure obtained by adding a first pressure (the pressure of the fuel discharged from the second discharge port of the fuel pump) acting on the lower portion of the plunger 130 to allow the valve head 134 to frictionally rise from the lower portion of the friction path 122 to the upper portion and a second pressure for compressing the spring 140 when the plunger 130 and the valve head 134 rise is set to be equal to or higher than a prescribed fuel pressure at the time of engine start-up when fuel is supplied from the fuel pump 13 to the engine.

[0070] For example, the first pressure acting on the lower part of the plunger 130 to allow the valve head 134 to frictionally rise from the lower part to the upper part of the friction path 122 is set to 1.5 bar, and the second pressure for compressing the spring 140 when the plunger 130 and the valve head 134 rise is set to 3 bar, so that the total pressure obtained by adding the first pressure and the second pressure can be set to 4.5 bar, which is the prescribed fuel pressure at the time of engine start-up when fuel is supplied from the fuel pump 13 to the engine.

[0071] Here, the operation flow of the valve system of the fuel pump according to the present disclosure having the above-mentioned configuration will be described as follows.

[0072] Figure 5 The operating state of the valve system according to the present disclosure during cold start of the engine is shown, wherein the left figure shows the operating state of the valve system before the fuel supply pressure reaches 4.5 bar, and the right figure shows the operating state of the valve system after the fuel supply pressure reaches 4.5 bar.

[0073] At the time of cold start of the engine, the engine can be started smoothly only when the fuel pump is driven and the pressure of the fuel supplied from the fuel pump to the engine reaches a prescribed fuel pressure at the time of engine start.

[0074] However, when the fuel is pumped from the fuel pump to the engine at the time of cold start of the engine, some of the fuel is discharged to the first injection pump and the second injection pump, so that some of the fuel at this time acts as flow loss, and therefore it takes a long time for the pressure of the fuel supplied from the fuel pump to the engine to increase to the specified fuel pressure required for starting, which leads to the problem of poor cold start performance and hinders the smooth starting of the engine.

[0075] In order to solve the above problems, Figure 5 As shown in the left figure, if the pressure of the fuel supplied from the fuel pump 13 to the engine is lower than the specified fuel pressure at the time of engine start-up, the valve head 134 is located at the lowest part of the friction path 122 of the second valve body 120, and the plunger 130 is located in the lower rising / descending path 112-2 of the plunger rising / descending path 112 of the first valve body 110, so that the injection pump side flow path 114 is maintained in a closed state. As a result, some of the fuel discharged from the fuel pump is not supplied to the first and second injection pumps through the injection pump side flow path 114, thereby preventing some of the fuel from acting as flow loss.

[0076] For example, when the pressure of the fuel supplied from the fuel pump 13 to the engine does not reach 4.5 bar as the prescribed fuel pressure at the time of engine startup, the jet pump side flow path 114 is maintained in the closed state.

[0077] That is, as described above, when the pressure of the fuel supplied from the fuel pump 13 to the engine is not equal to or higher than the total pressure of 4.5 bar (obtained by adding a first pressure of 1.5 bar acting on the lower part of the plunger 130 to allow the valve head 134 to frictionally rise from the lower part of the friction path 122 to the upper part and a second pressure of 3 bar used to compress the spring 140 when the plunger 130 and the valve head 134 rise), the injection pump side flow path 114 is maintained in a closed state by the plunger 130.

[0078] As described above, when the pressure of the fuel supplied from the fuel pump 13 to the engine does not reach 4.5 bar, which is the prescribed fuel pressure when the engine is started, the injection pump side flow path 114 is maintained in a closed state by the plunger 130, so that some of the fuel discharged from the fuel pump is not supplied to the first and second injection pumps through the injection pump side flow path 114, thereby preventing some of the fuel from acting as flow loss.

[0079] By cutting off the discharge of some fuel to the injection pump side flow path 114 and continuously driving the fuel pump, the fuel pressure supplied from the fuel pump 13 to the engine can be quickly increased to 4.5 bar, which is the prescribed fuel pressure at the time of engine starting.

[0080] refer to Figure 8 Compared with a conventional structure in which the time required to increase the pressure of the fuel supplied from the fuel pump to the engine to the specified fuel pressure when the engine is cold-started is generally delayed by about 1 second or longer, the present disclosure can shorten the time to about 250ms or less, and thus can start the engine quickly and smoothly even when the engine is cold-started, thereby improving the cold-start performance of the engine.

[0081] At this time, when the pressure of the fuel supplied from the fuel pump 13 to the engine is equal to or higher than 4.5 bar (which is the prescribed fuel pressure when the engine is started), the engine is started. Figure 5 As shown in the right figure, the plunger 130 rises to the upper rising / descending path 112-1 of the plunger rising / descending path 112, and the valve head 134 moves to the highest position of the friction path 122 while compressing the spring 140, so that the injection pump side flow path 114 is in an open state connected to the second discharge port 13-2 of the fuel pump 13.

[0082] That is, as described above, when the pressure of the fuel supplied from the fuel pump 13 to the engine is equal to or higher than the total pressure of 4.5 bar (obtained by adding a first pressure of 1.5 bar acting on the lower part of the plunger 130 to allow the valve head 134 to frictionally rise from the lower part of the friction path 122 to the upper part and a second pressure of 3.0 bar used to compress the spring 140 when the plunger 130 and the valve head 134 rise), the plunger 130 rises to the upper rising / descending path 112-1 of the plunger rising / descending path 112, so that the injection pump side flow path 114 is in an open state connected to the second discharge port 13-2 of the fuel pump 13.

[0083] Therefore, when fuel is discharged from the first discharge port 13-1 of the fuel pump 13 and pumped to the engine after the engine is started, some fuel can be discharged through the second discharge port 13-2 to flow to the first injection pump 12-1 and the second injection pump 12-2, thereby easily exerting the own functions of the first injection pump 12-1 and the second injection pump 12-2 to fill the fuel.

[0084] That is, the fuel existing in the first fuel storage space 10-1 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the first jet pump 12-1, and the fuel existing in the second fuel storage space 10-2 of the fuel tank 10 can be easily filled into the fuel storage cup 11 by the vacuum suction pumping of the second jet pump 12-2.

[0085] Figure 6 The operating state of the valve system according to the present disclosure when the engine is driven after the engine is started is shown, and in particular, it shows the operating state of the valve system when the engine is driven after the engine is started (low load of the engine - high load of the engine).

[0086] As described above, after the engine is started, the plunger 130 rises to the upper rising / descending path 112-1 of the plunger rising / descending path 112, and the valve head 134 rises to the highest position of the friction path 122 while compressing the spring 140, so that the injection pump side flow path 114 is in an open state connected to the second discharge port 13-2 of the fuel pump 13.

[0087] At this time, in the low load region and the medium load region of the engine, the pressure of the fuel supplied from the fuel pump 13 to the engine may drop below the prescribed fuel pressure at the time of engine start.

[0088] For example, although the fuel pressure supplied from the fuel pump to the engine is 5 bar in the high load region of the engine, the fuel pressure supplied from the fuel pump to the engine may drop to 3 bar, which is less than 4.5 bar, which is the prescribed fuel pressure when the engine is started, and in the low load region of the engine, the fuel pressure supplied from the fuel pump to the engine may drop to about 4 bar, which is less than 4.5 bar, which is the prescribed fuel pressure when the engine is started, even in the middle load region of the engine.

[0089] As described above, even if the pressure of the fuel supplied from the fuel pump 13 to the engine drops to below the prescribed fuel pressure at engine start in the low load area and the intermediate load area of ​​the engine, when the fuel pressure is equal to or higher than the second pressure (for example, 3 bar) used to compress the spring 140, the plunger 130 is continuously located in the upper rising / falling path 112-1 of the plunger rising / falling path 112, and the valve head 134 is also continuously located at the uppermost part of the friction path 122, so that the injection pump side flow path 114 can be continuously maintained in an open state.

[0090] More specifically, even if the pressure of the fuel supplied from the fuel pump 13 to the engine drops below the prescribed fuel pressure at engine start, when the fuel pressure is equal to or higher than the second pressure (e.g., 3 bar) for compressing the spring 140, a force 3 bar or more greater than the elastic restoring force of the spring 140 is applied to the plunger 130 to keep the spring 140 continuously in a compressed state. As a result, the plunger 130 is continuously located in the upper ascent / descendence path 112-1 of the plunger ascent / descendence path 112, and the valve head 134 is also continuously located at the uppermost part of the friction path 122, so that the injection pump side flow path 114 can be continuously maintained in an open state.

[0091] Therefore, in the low load area and the intermediate load area of ​​the engine, when the fuel is discharged from the first discharge port 13-1 of the fuel pump 13 and pumped to the engine, some of the fuel can be discharged through the second discharge port 13-2 to flow to the first injection pump 12-1 and the second injection pump 12-2 through the injection pump side flow path 114, thereby easily exerting the own function of the first injection pump 12-1 and the second injection pump 12-2 for filling the fuel.

[0092] At the same time, a general check valve can also be used as a jet pump control valve.

[0093] Of course, since a general check valve opens and closes at the same pressure, the check valve is opened at a specified fuel pressure to allow fuel to be smoothly supplied to the engine when the engine is cold started, thereby improving the cold start performance.

[0094] However, in the low load area or the intermediate load area after the engine is started, when the fuel supply pressure drops below the specified fuel pressure during the cold start of the engine, the general check valve may block the injection pump side flow path toward the injection pump, thereby losing the function of the injection pump itself, which sucks the fuel in the fuel tank into the oil storage cup and fills the oil storage cup with fuel, so that the problem of being unable to fill the fuel into the oil storage cup may occur.

[0095] On the contrary, as described above, the present invention opens the injection pump side flow path 114 after the engine is started, and then, as described above, allows the injection pump side flow path 114 to remain in an open state even between the low load area and the high load area of ​​the engine, so that the self functions of the first injection pump 12-1 and the second injection pump 12-2 that fill the fuel in the fuel tank into the oil storage cup after the engine is started can be smoothly maintained.

[0096] Figure 7 The operating state of the valve system according to the present disclosure is shown when the engine is shut down.

[0097] When the engine is turned off and the pressure of the fuel supplied to the engine from the fuel pump 13 is equal to or less than 5 bar, the valve head 134 moves to the lowest part of the friction path 122 of the second valve body 120 by the elastic restoring force of the spring 140, and the plunger 130 moves to the lower rising / descending path 112-2 of the plunger rising / descending path 112 of the first valve body 110, so that the injection pump side flow path 114 becomes in a closed state.

[0098] As described above, by closing the injection pump side flow path 114 until the pressure of the fuel supplied from the fuel pump 13 to the engine reaches the specified fuel pressure when the engine is started, the loss of fuel discharged to the first injection pump 12-1 and the second injection pump 12-2 when the engine is cold started can be eliminated, thereby shortening the time required for the pressure of the fuel supplied from the fuel pump 13 to the engine to increase to the specified fuel pressure when the engine is cold started, thereby improving the cold start performance of the engine.

[0099] In addition, the injection pump side flow path can be opened after the engine is started, and then the injection pump side flow path can be kept in an open state, thereby smoothly maintaining the function of the injection pump itself, which fills the fuel in the fuel tank into the oil storage cup after the engine is started.

[0100] As described above, although the present disclosure has been described as an exemplary embodiment, the scope of the present disclosure is not limited to the above-mentioned exemplary embodiment, and various modifications and improvements made by those skilled in the art using the basic principles of the present disclosure defined in the appended claims will also be included in the scope of the present disclosure.

Claims

1. A valve system for a fuel pump of a vehicle, the valve system comprising: An oil storage cup, wherein the oil storage cup is installed in the fuel tank; an injection pump, the injection pump being used to fill the fuel storage cup with fuel in the fuel tank; a fuel pump, on which a first discharge port for discharging the fuel in the oil storage cup to the engine and a second discharge port for discharging some of the fuel discharged to the engine to the injection pump are formed; and an injection pump control valve, the injection pump control valve being mounted on the second discharge port of the fuel pump, wherein the injection pump control valve is configured to close an injection pump side flow path toward the injection pump when the pressure of the fuel supplied from the fuel pump to the engine is lower than a prescribed fuel pressure at engine startup, to open the injection pump side flow path toward the injection pump when the pressure of the fuel is equal to or higher than the prescribed fuel pressure at engine startup, and to maintain the injection pump side flow path in an open state even between a low load region and a high load region of the engine after engine startup, Wherein, the injection pump control valve comprises: a first valve body having a plunger ascending / descending path having a predetermined height formed therein, and a jet pump side flow path toward the jet pump formed at a middle position of the plunger ascending / descending path; a second valve body provided in a structure having a friction path formed therein and formed at an upper portion of the first valve body to communicate with the first valve body; a plunger, the plunger being located in the plunger ascending / descending path to ascend / descend; a valve head positioned to frictionally contact the friction path and rise / fall; a rising / falling rod connected between the plunger and the valve head; and a spring connected between an upper end of the second valve body and an upper surface of the plunger to be compressed, Wherein, the friction path has locking protrusions formed at the upper and lower ends thereof, and the locking protrusions limit the rising / falling distance of the valve head.

2. The valve system according to claim 1, in, The plunger rising / falling path includes: an upper rising / falling path and a lower rising / falling path, the plunger is located in the upper rising / falling path to allow the injection pump side flow path to be opened, and the plunger is located in the lower rising / falling path to allow the injection pump side flow path to be closed.

3. The valve system according to claim 1, in, The valve head is formed as a spherical structure that is in frictional contact with an inner surface of the friction path.

4. The valve system according to claim 1, in, The total pressure is set to be equal to or higher than a specified fuel pressure when the engine is started, and fuel is supplied from the fuel pump to the engine when the engine is started. The total pressure is obtained by adding a first pressure acting on the plunger to allow the valve head to frictionally rise from a lower part to an upper part of the friction path and a second pressure for compressing the spring when the plunger and the valve head rise.

5. The valve system according to claim 4, in, When the pressure of the fuel supplied from the fuel pump to the engine is lower than the specified fuel pressure when the engine is started, the valve head is located at the lower part of the friction path, and the plunger is located in the lower rising / descending path of the plunger rising / descending path to keep the injection pump side flow path closed.

6. The valve system according to claim 4, in, When the pressure of the fuel supplied from the fuel pump to the engine is equal to or higher than the specified fuel pressure when the engine is started, the plunger rises to the upper rising / falling path of the plunger rising / falling path, and the valve head rises to the upper part of the friction path while compressing the spring to allow the injection pump side flow path to open.

7. The valve system according to claim 4, in, After the engine is started, in the low load area and the intermediate load area of ​​the engine, even if the pressure of the fuel supplied from the fuel pump to the engine drops below the prescribed fuel pressure at the time of engine start, when the pressure of the fuel is equal to or higher than the second pressure for compressing the spring, the plunger is continuously located in the upper rising / descending path of the plunger rising / descending path, and the valve head is also continuously located in the upper part of the friction path to keep the injection pump side flow path in an open state.

8. The valve system according to claim 1, in, A cover is detachably mounted on an upper end of the second valve body, the cover having the spring connected to a lower surface thereof.

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