Patent Grant
7631634
The present disclosure relates to valve arrangement in a fuel pump module that provides high pressure in a fuel line thereby ensuring optimal fuel pressure during engine starting.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Conventional vehicular fuel systems, such as those installed in automobiles, may employ a “return fuel system,” whereby a fuel supply tube or line is utilized to supply fuel from a fuel tank to an engine and a fuel return tube or line is utilized to return unused fuel from the engine to the fuel tank.
Typically, more modern vehicles employ a “returnless fuel system” that may be either mechanically or electrically controlled. In many returnless fuel systems, such as a mechanical returnless fuel system (“MRFS”) a fuel pump continuously pumps a constant flow of fuel from a fuel tank to the engine. In another type of returnless fuel system, such as an electronic returnless fuel system (“ERFS”), the voltage across the fuel pump is controlled to vary the fuel pumped to the engine. A pressure regulator controls the pressure of fuel directed to the engine, and discharges excess fuel back into the fuel tank. This eliminates the need for a return line, hence the term “returnless fuel system.”
When the engine is operating, fuel is delivered to the engine at a relatively low pressure, for example, at 400-450 kilopascals (kPa). The engine may then be turned off, and for a time period after the engine is turned off but still radiating heat, the fuel remaining in the fuel injector rail and the fuel line may be heated by the engine, other hot components of the vehicle, and/or high ambient air temperatures. Under these conditions, low pressure fuel in the fuel rail or any fuel lines may vaporize. As such, fuel vapor in the injector rail or fuel lines can cause vapor lock, which in turn, may hinder or prevent ignition or combustion during an attempted engine restart.
Prior known fuel systems lack a satisfactory means for managing fuel pressure and flow within the fuel system, both during and after an engine's operation, in an efficient, space-conscious manner.
A fuel pump module may employ a fuel pump, a pressure regulator, a fuel supply line check valve, a fuel line pressure relief valve, and a fuel pump module flange, which may be adapted to engage a fuel supply line that fluidly links the fuel pump module with a fuel injector rail. The pressure regulator may be adapted to maintain a predetermined fuel pressure between the fuel pump and the fuel supply line check valve. The fuel supply line check valve may be configured to facilitate a minimum fuel pressure in the fuel supply line while the relief valve may be configured to limit the maximum fuel pressure in the fuel supply line. The fuel supply line check valve, the relief valve, and the flange may be integrated to form a single, fluidly interconnected structure disposed within a fluid path between the pressure regulator and the fuel supply line. A single case or multiple cases molded together to form an integrated casing may house the fuel pump and the pressure regulator. The single, fluidly interconnected structure and the integrated casing may be fixedly engaged with each other to form a modular unit.
The supply line check valve and the pressure relief valve may be vertically arranged and fluidly parallel to each other. Alternatively, a single housing structure may house a vertically oriented supply line check valve and a horizontally oriented pressure relief valve, or a horizontally oriented supply line check valve and a vertically oriented pressure relief valve in the single housing structure. Furthermore, in yet another arrangement, the single housing structure may be welded to the flange to become integral and permanently fastened to the flange. The flange and the single housing structure may form a fluid passage that fluidly links the pressure relief valve and the supply line check valve. The supply line check valve and the pressure relief valve may be fluidly linked in a hoseless fashion to increase durability and reduce parts.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. With reference to
With reference mainly to
Continuing with
The pressure regulator 56, in addition to passing fuel into the feed line 58 at the desired pressure in accordance with the reference setting pressure of the pressure regulator, re-circulates excess fuel, beyond that which is needed to maintain the reference pressure, back into the reservoir 36 so that it again may be drawn into the fuel pump 50. Relatively low pressure fuel, or rather that pressure to which the regulator is manufactured, is also routed from the pressure regulator 56 to a jet pump 59 disposed near or at the bottom of the fuel tank 16, as depicted in
The pressure regulator 56 is fluidly linked to a supply line check valve 60 and a relief valve 62 via the feed line 58. The supply line check valve 60 is arranged fluidly parallel to the relief valve 62 (
When the engine is not running, such as immediately after turning off the ignition, heat from the engine 12 may heat the fuel in the fuel supply line 14, thereby increasing the pressure in the fuel supply line 14 above the reference pressure. The fuel in the fuel supply line 14 may also be heated by the ambient air, as opposed to or in addition to heat from the engine 12, such as on a very hot summer day such that the ambient air is hot enough to raise the temperature and thus the pressure of the fuel in the fuel supply line 14 above the reference pressure. Still yet, heat may emanate from black pavement or asphalt which has been heated by sunlight. In one example, if a car is driven so as to bring the engine temperature up to a steady operating temperature, and then the car is parked on asphalt that has been subjected to direct sunlight at least 2 hours, as an example, and then the vehicle ignition is turned off, the fuel temperature may rise. Additionally, the fuel pressure in the fuel line 14 may rise above the combined pressure of the spring 64 and the pressure regulator pressure (pressure in line 58). If the fuel pressure in the fuel supply line 14 rises above a maximum allowable pressure or maximum predetermined pressure, the biasing force of the relief valve spring 64 is overcome or countered with force such that the relief valve 62 opens, thereby allowing fuel of a pressure higher than the set pressure of the relief valve 62 to flow out of the fuel supply line 14. As a result, the pressure in the fuel supply line 14 decreases below the maximum allowable pressure. From the relief valve 62, fuel pressure may be vented back into the feed line 58. If the pressure in the feed line 58 is above the reference pressure, the pressure regulator 56 discharges fuel back into the reservoir 36 to maintain the reference pressure in the feed line 58. The reservoir 36 is open to the fuel tank 16, which may be vented to a charcoal canister.
The supply line check valve 60 and the relief valve 62 may be arranged vertically and physically parallel to each other, as shown in
In another embodiment,
The supply line check valve 60 and the relief valve 62 may be disposed below the flange 28, as shown in
Continuing with reference to
In this configuration, upon actuation of the relief valve 62 to relieve pressure in the fuel supply line 14, fuel travels through the relief outlet port 82, through the connector 86 and the connecting hose 88, into the feed line port 70 via the port 84, and into, that is down through, the feed line 58, into the pressure regulator 56, and back into the reservoir 36 (only if the feed line pressure exceeds the pressure regulator set point), which is ultimately vented to the tank at approximately atmospheric pressure, as previously described. Again, an advantage of the embodiment depicted in
In yet another embodiment depicted in
With continued reference to
To create a fuel flow path from the interior of supply line stem 76 to the feed line port 70, the flange 28 has a rim 90 or legs protruding from it on an underside of the flange 28. Additionally, the single housing 67 has a rim 92 or legs 92 protruding upward from it such that the rim 90 and rim 92 meet to form a joint. Such a joint at interface surfaces 91, 93 of the rims 90, 92 may be created using hot plate welding and be leak-proof and permanent. Interface surface 91 being on rim 90 while interface surface 93 is on rim 92. Because the rims 90, 92 are protrusions, a cavity 94 is formed by their joining such that fuel is permitted to flow in accordance with flow arrow 96 from the fuel supply line 14 to the feed line 58. An advantage of the embodiment depicted in
There are multiple advantages to the teachings of the present disclosure. First, the fuel pump module 18 is capable of delivering fuel at a relatively low reference pressure to the engine 12 during operation, while maintaining high fuel pressure in the fuel supply line 14 when the engine 12 is off. Such is possible because the spring 63 in the check valve 60, which permits fuel to flow to the engine via the fuel supply line 14, is set to open at a pressure lower than the spring 64 in the relief valve 62, which permits fuel to flow from the engine, or rather from the fuel supply line 14.
The diameter of orifice 87 of
The advantage of maintaining high pressure in the fuel supply line 14 and the injector rail 24 is that high pressure, that is, pressure high enough to prevent fuel vaporization, prevents vaporization of the fuel and thus, vapor lock, thus increasing the reliability of starting of the engine 12, especially during hot days or when the fuel supply line 14 and injector rail 24 are susceptible to fuel vapor lock. Further, high fuel pressure in the fuel supply line 14 and the injector rail 24 at start-up facilitates more efficient and complete combustion, thus reducing fuel consumption, due to longer starting times, and prolonged noxious exhaust emissions during engine starting. Fuel consumption may be reduced because the engine 12, as equipped with the teachings above, will start more quickly when the pressure in the fuel supply line 14 is maintained at a higher pressure even when the engine 12 is not operating. That is, no time is spent creating pressure in the fuel supply line 14 in the few seconds or even a portion of a second prior to actual sustained combustion of the engine 12. The higher pressure is maintained as a result of the spring stiffness of the relief valve.
There are multiple advantages to the integral construction of the fuel pump module 18 according to the present disclosure. Integrally forming the single housing structure 66 to the flange 28 mitigates a potential leak source by joining the two components as one. Joins and couplings are reduced. A single modular unit also saves space within the fuel tank 16 since hoses typically need nipples or leads for connection. Such leads utilize precious space within the module and fuel tank. Further, integral construction facilitates easy installation of the fuel pump module 18 into the fuel tank 16. The integral construction also provides convenient access for servicing components of the fuel pump module 18, as disengaging the flange 28 from the fuel tank 16 enables easy access to the entire fuel pump module 18, which may easily be lifted from the tank without components, such as valves, etc. dangling from connection hoses. The single housing structure 67 saves space in the fuel pump module 18 and the fuel tank 16 by locating the valves 60, 62 as close as possible to the flange 28, with no hoses, or just a single hose. Additionally, selectively placing the valves 60, 62 in specific horizontal or vertical arrangements also efficiently utilizes space within the module 18 and fuel tank 16. Finally, with integral construction, parts will not become detached thus compromising functionality of the module during operation.
The description of the present disclosure is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
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| Number | Date | Country | |
|---|---|---|---|
| 20090120413 A1 | May 2009 | US |
