FUEL SUPPLY SYSTEM WITH INTEGRATED CHECK VALVE

Abstract

Fuel supply system (50) for providing fuel to cylinders (14) in a power engine (12), comprising: an elastic fuel line (64, 200) positioned between a first fuel pump (54) and a second fuel pump (66) and a check valve (62, 210, 400, 500) positioned in the elastic fuel line (64, 200), wherein the check valve (62, 210, 400, 500) includes an outer housing (216, 406, 502) with a circumferential surface (218), wherein the circumferential surface (218) is the outermost valve surface, and wherein the circumferential surface (218) has a larger diameter (219) than an unstretched inner diameter (207) of the elastic fuel line (64, 200), characterized by the fact that the circumferential surface (218) is in surface contact with a housing (202) of the elastic fuel line (64, 200).

Description

[0001] The present disclosure relates to a fuel supply system in an engine.

[0002] Fuel supply systems are used in vehicles to deliver fuel to cylinders in the engine. Some fuel supply systems may include multiple fuel pumps, such as a high-pressure fuel pump and a low-pressure fuel pump, to deliver high-pressure fuel to the cylinders. Increasing the pressure of the fuel supply system can enable an increase in combustion efficiency, thereby reducing fuel consumption and / or increasing power output. However, fuel supply systems can experience pressure pulsations at various points in the system. For example, pressure pulses may occur between the fuel pumps and between the fuel rail and the high-pressure fuel pump. As a result, the longevity of the pumps, fuel rail, etc., can be affected.due to the degradation of components caused by pressure pulsations in the system. These pressure pulsations can also negatively impact the metering of fuel delivered to the combustion chamber, thereby reducing combustion efficiency. Furthermore, customer satisfaction is also reduced by noise, vibration, and harshness (NVH) caused by the pulsations.

[0003] US 5 251 664 A discloses a check valve in a fuel supply system between a pump and a fuel tank. The check valve is designed to reduce ticking noises generated during valve operation. It is understood that the check valve disclosed in US 5 251 664 A is configured to connect an upstream and downstream fuel channel. Furthermore, the check valve disclosed in US 5 251 664 A is a stand-alone component in the fuel supply system. As a result, the bulkiness of the fuel supply system is increased. Furthermore, the valve disclosed in US 5 251 664 A is L-shaped. This type of shape increases losses in the fuel supply system. DE 10 2011 111 579 A1 discloses a fluid delivery system with a check valve connecting two sections of a fluid line.DE 10 2009 045 898 A1 discloses a fuel injection system with a hose having an elastically deformable wall. A quick-release coupling for a hose connection in fuel lines is disclosed in DE 10 2007 032 027 A1. US 7 444 990 B1 discloses a check valve with a leakage path. US 6 929 023 B2 discloses a check valve for plastic pipes in underground applications.

[0004] The present inventors have recognized the above problems and developed a fuel supply system for supplying fuel to cylinders in an engine. The fuel supply system according to the invention includes a flexible fuel line positioned between a first fuel pump and a second fuel pump, and a check valve positioned in the flexible fuel line. The check valve includes an outer housing having a circumferential surface, the circumferential surface being the outermost valve surface, and the circumferential surface having a larger diameter than an unstretched inner diameter of the flexible fuel line. The circumferential surface is in surface contact with a housing of the flexible fuel line.

[0005] Such sizing of the check valve and the corresponding fuel line enables secure attachment of the check valve to the fuel line. In particular, the expanded fuel line exerts a radial force on the check valve to secure the valve at a desired location in the fuel line. This allows the check valve to be easily integrated into existing fuel lines, if desired, without introducing a separate check valve. As a result, the compactness of the fuel supply system can be increased. Furthermore, the check valve weakens pressure pulsations in the fuel line, thereby reducing NVH in the fuel supply system.Thus, the technical results achieved via the above-mentioned engine system include increasing the compactness of the system and reducing pulsations in the fuel supply system, thereby increasing the longevity of the system and reducing NVH in the system.

[0006] The above advantages and other advantages and features of the present description will be readily apparent from the following detailed description, considered alone or in conjunction with the accompanying drawings.

[0007] It should be understood that the above summary is intended to introduce, in simplified form, a selection of concepts that are further described in the detailed description. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any of the disadvantages noted above or in any other part of this disclosure. Moreover, the present inventors are aware of the above problems but do not assume them to be known. Fig. 1 shows a schematic representation of a vehicle with an engine and a fuel supply system; Fig. 2 shows an illustration of an exemplary check valve positioned in a flexible fuel line; Fig. 3 shows a representation of another view of the Fig. 2 shown check valve; Fig. 4 shows another example of a check valve positioned in a fuel line; Fig. 5 shows another exemplary check valve and Fig. 6 shows a method for operating a fuel supply system.

[0008] A fuel supply system is described herein. The fuel supply system includes a check valve positioned in a flexible fuel line. The check valve includes an outer housing having a circumferential surface with a larger diameter than an unstretched inner diameter of the flexible fuel line. Such sizing of the check valve and fuel line enables, if desired, secure integration of the check valve into the fuel line without splitting the fuel line to add a standalone check valve assembly. Consequently, the compactness of the fuel supply system can be increased by integrating the check valve into an existing fuel line, if desired. Furthermore, it is understood that the pressure pulsations can be generated by operating a fuel pump upstream of the check valve.It is further understood that the check valve is configured to allow fuel flow therethrough in a downstream direction when the pressure in the fuel line exceeds a threshold. As a result, pressure pulsations in the fuel line are reduced. Consequently, NVH in the fuel supply system is reduced, thereby increasing the longevity of the fuel supply system component and customer satisfaction.

[0009] Fig. 1 shows a schematic representation of a vehicle 10 including an engine 12. The engine 12 is configured to implement internal combustion operation. For example, a four-stroke combustion cycle may be implemented, including an intake stroke, a compression stroke, a power stroke, and an exhaust stroke. However, other types of combustion cycles may be used in other examples. In this manner, motive power may be generated in the vehicle 10. It is understood that the engine may be coupled to a transmission for transmitting rotational power generated in the engine to wheels of the vehicle.

[0010] The engine 12 includes one cylinder 14. However, engines with a different number of cylinders and configurations have also been contemplated. For example, the cylinders may be arranged in an inline configuration in which cylinders are positioned in a straight line, a horizontally opposed configuration, a V-configuration, etc. Thus, in one example, the cylinders may be arranged in banks. The cylinder 14 is mechanically coupled to a crankshaft (not shown).

[0011] The vehicle 10 includes an intake system 16 configured to supply air to the cylinder 14. The flow connection between the intake system 16 and the cylinder 14 is indicated by arrow 18. The intake system 16 may include various components, such as intake ports, a filter, a throttle, an intake manifold, etc.

[0012] Further, the vehicle 10 includes an exhaust system 20 configured to receive exhaust gas from cylinder 14. The flow connection between cylinder 14 and the exhaust system 20 is indicated by arrow 22. The exhaust system 20 may include exhaust ports, an exhaust manifold, emission control devices (e.g., particulate filters, catalysts), etc.

[0013] The vehicle 10 further includes a fuel supply system 50 configured to provide fuel to the cylinder 14. The fuel supply system 50 includes a fuel tank 52 configured to store a suitable combustible fuel, such as gasoline, diesel, alcohol, etc. The fuel tank 52, in this example, includes a flange 53. The flange 53 is attached to the tank and provides a mounting feature for the fuel supply module.

[0014] A lower pressure fuel pump 54 is also included in the fuel supply system 50. In the illustrated example, the lower pressure fuel pump 54 is included in the fuel tank 52. However, in other examples, the lower pressure fuel pump 54 may be positioned at least partially external to the fuel tank 52. The lower pressure fuel pump 54 is configured to direct fuel to downstream components.

[0015] A fuel filter 56 included in the fuel supply system 50 is positioned downstream of the lower-pressure fuel pump 54 and is therefore in fluid communication with the lower-pressure fuel pump. The fuel filter 56 is configured to remove unwanted particulates from the fuel flowing through it. A throttle device 58 is also in fluid communication with the lower-pressure fuel pump 54. The throttle device 58 is configured to move inaccessible fuel to the fuel supply module.

[0016] A valve 60 is positioned downstream of the fuel filter 56 and is therefore in fluid communication with the fuel filter 56 and the lower pressure fuel pump 54. The valve 60 is a two-way valve in the example shown. The valve 60 has a first configuration that allows fuel flow to downstream components. The valve 60 has a second configuration that prevents fuel flow to downstream components and allows fuel flow back to the fuel tank 52. The valve 60 may be electronically controlled via the controller, in one example, an electric solenoid valve 100. However, in other examples, the valve 60 may be passively controlled.

[0017] Furthermore, the fuel supply system 50 includes a check valve 62. The check valve 62 is configured to allow fuel flow in a downstream direction therethrough when the pressure of the fuel in the fuel line upstream of the valve exceeds a threshold. The check valve 62 is integrated into the fuel line 64 in the example shown. The fuel line 64 extends from the valve 60 to a higher pressure fuel pump 66. Thus, the fuel line 64 provides fluid communication between the valve 60 and the higher pressure fuel pump 66. The check valve 62 will be described with reference to Fig. 2-4. The higher pressure fuel pump 66 is in fluid communication with the check valve 62. Therefore, the check valve 62 is positioned between the higher pressure fuel pump 66 and the lower pressure fuel pump 54. The higher pressure fuel pump 66 is in fluid communication with a fuel rail 68 and a fuel injector 70 that delivers metered amounts of fuel to the cylinder 14. The fuel injector 70 is directly coupled to the cylinder 14 to provide injection to the cylinder, known in the art as direct injection. Therefore, the fuel injector 70 may be referred to as a direct fuel injector. Additionally, or alternatively, port fuel injection may also be provided in the engine 12.

[0018] A fuel line 72, indicated by an arrow, provides fluid communication between the valve 60 and the fuel filter 56. Furthermore, a fuel return line 74 is in fluid communication with the valve 60 and includes an outlet opening into the fuel tank 52. A fuel line 76 also provides fluid communication between the lower pressure pump 54 and the fuel filter 56. It is understood that the above-mentioned fuel lines are included in the fuel supply system 50. The fuel supply system 50 may also include an external filter 80 for increasing the filtration of fuels.

[0019] A controller 100 may be included in the vehicle 10. The controller 100 may be configured to both receive signals from sensors in the vehicle and send command signals to components. Various components in the vehicle 10 may be at least partially controlled by a control system including the controller 100 and by input from a vehicle operator 132 via an input device 130. In this example, the input device 130 includes an accelerator pedal and a pedal position sensor 134 for generating a proportional pedal position signal PP. The controller 100 is in Fig. 1 as a microcomputer including a processor 102 (e.g., a microprocessor unit), input / output ports 104, an electronic storage medium for executable programs and calibration values, illustrated in this particular example as a read-only memory (ROM) 106 (e.g., a read-only memory chip), a random access memory (RAM) 108, a retained memory (KAM) 110, and a data bus. The storage medium read-only memory 106 may be programmed with computer-readable data representing instructions executable by a processor 102 for performing the methods described below, as well as other variations anticipated but not specifically listed. As shown, the lower pressure fuel pump 54 and the higher pressure fuel pump 66 receive control signals from the controller 100. Therefore, the controller 100 may adjust the output of the fuel pumps (54 and 66).Fuel injector 70 also receives a control signal from controller 100. Therefore, fuel injector 70 may be configured to adjust the amount and timing of fuel delivered to cylinder 14 from fuel injector 70. Valve 60 also receives a control signal from controller 100.

[0020] Fig. 2 shows an exemplary elastic fuel line 200. The fuel line 200 can be Fig. 1. Therefore, the flexible fuel line 200 can be used with a higher pressure fuel pump, such as the one shown in Fig. 1, and a fuel pump with lower pressure, such as the one shown in Fig. 1. More specifically, in one example, the flexible fuel line 200 may extend between a lower pressure fuel pump and a higher pressure fuel pump. As shown, the fuel line 200 includes a housing 202. Fuel flows through the flexible fuel line 200 in the direction shown by arrow 204. The flexible fuel line 200 includes a plurality of layers 206. Thus, in the example shown, the flexible fuel line is a multi-layer fuel line. However, in other examples, the flexible fuel line may only include a single layer. Additionally, the flexible fuel line 200 has an unstretched inner diameter 207.It is understood that the unstretched inner diameter includes a condition of the fuel line in which substantially equal pressure is exerted on the inside and outside of the fuel line.

[0021] A check valve 210 is positioned in the fuel line 200. The check valve 210 can Fig. 1. The fuel line 200 at least partially encloses the check valve 210. The check valve 210 includes an upstream end 212 (e.g., front end) and a downstream end 214 (e.g., rear end). The upstream end 212 includes a curved front surface 215. Moreover, the outer diameter of the upstream end 212 is larger than the outer diameter of the downstream end 214. The curvature of this surface allows the valve to be inserted into the fuel line 200 without causing damage to the fuel line housing. As shown, the downstream end 214 is spaced from the housing 202 of the flexible fuel line 200. In other words, the downstream end 214 is not coupled or attached to the housing 102.The check valve 210 is configured to allow fuel flow therethrough in a downstream direction when the pressure in the flexible fuel line 200 upstream of the valve exceeds a threshold. In one example, the threshold is a few kPa higher than the downstream pressure. It is understood that the check valve 210 attenuates pressure pulses passing through the fuel line 200, thereby reducing NVH in the fuel delivery system. As a result, the likelihood of component degradation is reduced and component longevity is increased. Furthermore, customer satisfaction is also increased when NVH is reduced. The check valve 210 further includes an outer housing 216 having a circumferential surface 218. The circumferential surface 218 is the outermost valve surface and, in the example shown, is in surface contact with the housing 202 of the flexible fuel line 200.In this way, fuel can be substantially prevented from flowing between the circumferential surface and the housing. It should further be understood that the outer housing 216 includes additional circumferential surfaces having smaller diameters / radii than the outermost circumferential surface. The outer housing 216 encloses valve components, such as a spring, valve channels, etc. The diameter 219 of the circumferential surface 218 is illustrated. Furthermore, in the example shown, a cross-section of the circumferential surface perpendicular to a central axis 250 of the check valve is circular. However, other check valve geometries have also been contemplated.

[0022] In one example, the diameter 219 of the circumferential surface is greater than 105% of the unstretched inner diameter 207 of the elastic fuel line. Further, the diameter 219 of the circumferential surface is between 101% and 120% of the unstretched inner diameter 207 of the elastic fuel line. Furthermore, in one example, the diameter 219 of the circumferential surface is less than 5% of a maximum threshold strain of the elastic fuel line 200. In this way, the check valve 210 can be secured in a desired location via an elastic force applied to the valve via the elastic fuel line without stretching the elastic fuel line beyond a desired value, which may damage the line. As a result, the check valve 210 is integrated internally within the fuel line, thereby increasing the compactness of the fuel supply system.Furthermore, a ratio of an outer diameter of the upstream end 212 and the diameter of the circumferential surface 218 is 115 to 125%.

[0023] Furthermore, the elasticity of the fuel line 200 can be up to 130% of the original size. Furthermore, the elasticity of the fuel line 200 is greater than the elasticity of the check valve 210. Furthermore, in one example, the elasticity of the fuel line 200 can be greater than the elasticity of upstream and / or downstream fuel lines in the fuel supply system.

[0024] Furthermore, a tapered surface 220 of the outer housing 216 extends from the upstream end 212 to the outermost peripheral surface 218. A diverging angle 222 of the tapered end surface 220 extending from the upstream end 212 is between 20° and 40°. Furthermore, in one example, the downstream end 214 of the check valve 210 is positioned more than 15 mm from an end of the flexible fuel line 200.

[0025] In Fig. 2, a quick-connect coupling 221 is also shown. The quick-connect coupling 221 is coupled to the flexible fuel line 200. Furthermore, the quick-connect coupling 221 may be coupled to downstream components, such as a higher pressure fuel pump or a fuel line. It is understood that the quick-connect coupling may include a barbed fitting feature for sealing a fuel line. In one example, the quick-connect coupling 221 may be spaced at least 5 millimeters (mm) from the downstream end 214 of the check valve 210. The section plane 260 illustrating the Fig. 3 shown cross section is also defined in Fig. 2 shown.

[0026] Fig. 3 shows a cross-sectional view of the Fig. 2 shown check valve 210. In particular, Fig. 3 the downstream end 114 of the check valve 210. The check valve 210 includes drain channels 300 configured to drain fuel under non-operating conditions.

[0027] Fig. 4 shows an exemplary check valve 400 positioned in a device 402. The device 402 may, in one example, be a quick-connect device. In such an example, the quick-connect device may be positioned between a higher-pressure fuel pump and a lower-pressure fuel pump, in Fig. 1. Furthermore, the quick-connect device may comprise plastic and / or steel. In another example, device 402 may be a higher-pressure pump fitting.

[0028] As shown, the check valve 400 includes a plurality of teeth 404 that extend around the circumference of the valve housing 406 and may be part of the quick connect body or part of a high-pressure pump inlet fitting. The teeth 404 are formed by raised portions and depressed portions. Thus, the teeth can be thought of as recessed channels. As shown, the teeth have an equivalent outer circumference. However, in other examples, the circumference of the teeth may vary along their lengths and / or between the teeth. The teeth 404 are spaced approximately 1 millimeter apart and have a height of approximately half a millimeter. These teeth 404 may be flat or have a special feature to allow them to properly retain the check valve.

[0029] Fig. 5 shows another exemplary check valve 500. In particular, a cross-section of the check valve 500 is shown. The check valve 500 includes an outer housing 502. Furthermore, the check valve 500 includes teeth 504. The teeth 504 are contained within the housing 502. Furthermore, the teeth 504 include circumferential surfaces 506. The circumferential surfaces of one or more of the teeth may be larger than an unstretched inner diameter of a flexible fuel line in which the check valve 500 is positioned. Thus, it is understood that the check valve 500 may be used in a flexible fuel line, such as the one shown in Fig. 2 shown elastic fuel line 200.

[0030] Continue on Fig. 5, drain channels 508 are shown in check valve 500. Additional drain channels may also be included in check valve 500. In particular, the additional drain channels may be included in the circumferential surface of the valve. For example, the drain channels may extend through the teeth. The drain channels 508 in check valve 500 are configured to allow fuel to drain under non-operating conditions. In particular, the drain channels 508 may allow fuel flow from orifice 510 through the valve past an obstruction element 512 (e.g., a ball) included in valve 500. It should be understood that the size of the drain channels may be selected based on desired drain characteristics of the valve.

[0031] The obstruction element 512 is attached to a spring 514. The obstruction element 512 and the spring 514 can cooperate to allow and block flow through the check valve 500 based on the pressure of the fuel line or other component upstream of the valve. In a closed configuration, the obstruction element 512 sits on and seals against an inner surface 516 of the check valve 500. In an open configuration, the obstruction element 512 is spaced from the inner surface 516 and allows fuel flow through the valve in a downstream direction. Furthermore, the spring 514 is coupled to a stop 518. The stop 518 can limit movement of the spring 514.

[0032] Fig. 6 shows a method 600 for operating a fuel supply system. The method 600 can be implemented via the method described above with reference to Fig.1 discussed fuel supply system 50 or via another suitable fuel supply system.

[0033] The method includes, at 602, dampening pressure pulsations passing from a higher-pressure fuel pump to a lower-pressure fuel pump via a check valve positioned in an elastic fuel line between the higher-pressure fuel pump and the lower-pressure fuel pump, the check valve including an outer housing with a circumferential surface having a larger diameter than an unstretched inner diameter of the elastic multi-layer fuel line. In this way, the check valve can be secured in the fuel line via an elastic restoring force exerted on the valve via the fuel line. As a result, the check valve can be integrated into an existing fuel line, if desired, thereby reducing the cost of the fuel supply system and increasing the compactness of the system.In one example, the check valve is configured to allow fuel flow therethrough when the upstream fuel pressure in the flexible fuel line exceeds the downstream fuel pressure. As a result, the check valve reduces NVH in the fuel delivery system, thereby increasing component longevity and customer satisfaction. Next, at 604, the method includes directing fuel from the check valve to the high-pressure fuel pump.

[0034] It should be appreciated that the example control and estimation methods included herein may be used with various engine and / or vehicle system configurations. The particular methods described herein may represent one or more of a number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like. Thus, various illustrated acts, operations, and / or functions may be performed in the order illustrated, in parallel, or, in some cases, omitted. Likewise, the processing order may not necessarily achieve the features and advantages of the example embodiments described herein, but is provided for convenience of illustration and description.One or more of the depicted actions, operations, and / or functions may be performed repeatedly depending on the particular strategy employed. Furthermore, the depicted actions, operations, and / or functions may graphically represent code to be programmed into the non-volatile memory of the computer-readable storage medium in the engine control system.

[0035] It is understood that the configurations and methods disclosed herein are merely exemplary, and that these particular embodiments should not be considered in a limiting sense, as numerous variations are possible. For example, the above technology may be applied to V-6, I-4, I-6, V-12, horizontally opposed four, and other engine types. Thus, the subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and / or characteristics disclosed herein.

Claims

[1] A fuel supply system (50) for providing fuel to cylinders (14) in an engine (12), comprising: an elastic fuel line (64, 200) positioned between a first fuel pump (54) and a second fuel pump (66) and a check valve (62, 210, 400, 500) positioned in the elastic fuel line (64, 200), the check valve (62, 210, 400, 500) including an outer housing (216, 406, 502) having a circumferential surface (218), the circumferential surface (218) being the outermost valve surface, and the circumferential surface (218) having a larger diameter (219) than an unstretched inner diameter (207) of the elastic fuel line (64, 200), characterized by , that the peripheral surface (218) is in surface contact with a housing (202) of the elastic fuel line (64, 200). [2] The fuel supply system (50) of claim 1, wherein the fuel line (64, 200) is a multi-layer fuel line. [3] Fuel supply system (50) according to claim 1, wherein the fuel line (64, 200) is a polyamide fuel line. [4] Fuel supply system (50) according to claim 1, wherein the elastic fuel line (64, 200) is coupled to a quick coupling (221) downstream of the check valve (62, 210, 400, 500). [5] The fuel supply system (50) of claim 4, wherein the quick connector (221) is spaced at least 5 millimeters (mm) from a downstream end (214) of the check valve (62, 210, 400, 500). [6] The fuel supply system (50) of claim 1, wherein the check valve (400) includes a plurality of teeth (404) extending circumferentially around the outermost valve surface of the check valve (400). [7] The fuel supply system (50) of claim 1, wherein the check valve (210, 500) includes drain channels (300, 508) directly connected upstream and downstream for draining the high pressure side back to the low pressure side of the fuel supply system (50) under non-operating conditions. [8] The fuel supply system (50) of claim 1, wherein the diameter (219) of the peripheral surface (218) of the outer housing (216) is greater than 105% of the unstretched inner diameter (207) of the fuel line (64, 200). [9] The fuel supply system (50) of claim 1, wherein the diameter (219) of the peripheral surface (218) of the outer housing (216) is between 101% and 140% of the unstretched inner diameter (207) of the fuel line (64, 200). [10] The fuel supply system (50) of claim 1, wherein a diverging angle (222) of a tapered end surface (220) extending from an upstream end (212) of the check valve (210) is between 20° and 40°.

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