Patent Application
20110204268
The invention relates to fuel supply systems and, more particularly, to a fuel pressure regulator having a fuel tube that minimizes or eliminates resonant oscillation of a valve element when the regulator is exposed to turbulent fuel flow.
Most conventional automotive fuel systems use fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail which is supplied with fuel by a fuel pump. The pressure at which the fuel is supplied to the fuel rail must be metered to ensure the proper operation of the fuel injector. Metering is carried out using a pressure regulator that controls the pressure of the fuel in the system at all engine rpm levels.
A conventional flow through pressure regulator is disclosed in U.S. Patent Publication No. 2006/0108007 A1 and includes a lower housing having a fuel inlet wherein a flow of fuel through the inlet communicates with a valve assembly through a fuel chamber defined by a fuel tube. In an open position of a valve element, the valve assembly regulates the flow of fuel through the lower housing to a fuel outlet. In a closed position, the valve element rests on a valve seat to prohibit the flow of fuel from the fuel chamber to the fuel outlet. A valve biasing member biases the valve element toward the fuel chamber in opposition to pressure extend on the valve element by the fuel in the fuel chamber. During normal operation, there is a potential for the valve biasing member to reach a resonant frequency and oscillate when turbulent flow occurs at the inlet, since fuel flow through flow areas of the regulator is balanced. Turbulent flow within the fuel system makes it difficult to determine if the valve element will have the appropriated biased movement in a single direction. The turbulent flow may result in unwanted noise being generated in the fuel system.
To reduce noise, conventionally, the cross section of the fuel tube of the regulator has been modified to create different inside diameters throughout the length of the tube. However, this approach has the disadvantage that many different parts are required for many specific applications, and it is difficult to ensure that the proper part is installed in the specific fuel regulator application.
Thus, there is a need to provide an improved flow through fuel pressure regulator that prevents or minimizes oscillation of the valve element when the regulator is exposed to turbulent fuel flow.
An objective of the present invention is to fulfill the need referred to above. In accordance with the principles of an embodiment, this objective is obtained by providing a flow through pressure regulator including a fuel tube having an inlet end constructed and arranged to receive fuel, an outlet end, and a fuel chamber between the inlet end and the outlet end. The outlet end defines a valve seat. A valve element is constructed and arranged to engage the valve seat in a closed position to prohibit flow of fuel from the inlet end to the outlet end. A valve biasing member is constructed and arranged to bias the valve element towards the valve seat in opposition to pressure exerted on the valve element by the fuel in the fuel chamber, and to permit the valve element to move to an open position permitting flow of fuel past the outlet end, when pressurized fuel in the fuel chamber is sufficient to move the valve element, against the bias of the valve biasing member, from engagement with the valve seat. The fuel tube includes pressure differential creating structure at the outlet end thereof constructed and arranged to create a pressure differential around the valve element and cause unbalanced fuel flow at the outlet end to promote the valve element to move towards a certain location at the outlet end when the valve element moves to the open position.
In accordance with another aspect of the invention, a fuel tube is provided for a flow through fuel pressure regulator. The fuel tube includes a body having an inlet end constructed and arranged to receive fuel, an outlet end, and a fuel chamber between the inlet end and the outlet end. The outlet end defines a valve seat constructed and arranged to engage with a valve element of the regulator. Pressure differential creating structure is provided at the outlet end that is constructed and arranged to create a pressure differential around the valve element and cause unbalanced fuel flow at the outlet end to promote the valve element to move towards a certain location at the outlet end of the fuel tube when the valve element moves from engagement with the valve seat to an open position.
In accordance with yet another aspect of the invention, a method is provided to prevent a valve element of a flow through pressure regulator from resonating in an open position thereof. The method provides a fuel tube having an inlet end constructed and arranged to receive fuel, an outlet end, and a fuel chamber between the inlet end and the outlet end. The outlet end defines a valve seat constructed and arranged to engage with a valve element of the regulator. A pressure differential is created around the valve element that causes unbalanced fuel flow at the outlet end to promote the valve element to move towards a certain location at the outlet end of the fuel tube when the valve element moves from engagement with the valve seat to the open position.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.
The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which:
With reference to
The fuel tube 30 defines a valve seat 70 that cooperates with a valve element 80 that is movably disposed between a closed and an open position. In the closed position, the valve element 80 engages and seals against the seating surface of the valve seat 70 and prevents fuel flow past the valve seat 70. The valve element 80 is biased into the closed position by valve biasing member 90. Valve biasing member 90 is held in place by lower housing 20 which crimps over the outer edge of valve biasing member 90. Others skilled in the art may choose to affix the valve biasing member 90 to lower housing 20 with a weld or clip. Pressurized fuel flows through and accumulates in fuel chamber 40 until the pressurized fuel contacts the bottom surface of the valve element 80. The pressurized fuel will then push valve element 80, against the bias of the valve biasing member 90, off of valve seat 70 into an open position. The fuel flows through the fuel tube 40 and past the valve seat 70. In manufacturing the valve seat 70, the sealing surface is preferably coined to ensure smooth sealing between the valve element 80 and the valve seat 70.
Once the pressurized fuel is released, the valve element 80 is then biased back into the closed position by the valve biasing member 90. Valve biasing member 90 functions to hold the valve element 70 of the flow through pressure regulator 10 in a closed position at a predetermined amount of pressure that is related to the pressure desired by the flow through pressure regulator 10 specification.
In the preferred embodiment, the valve element 80 is shaped as a sphere and maintains a free floating configuration. The valve element 80 is preferably made of ceramic consisting of alumina oxide, to prevent galling from occurring during coining and to reduce wear of the valve seat. The valve element 80 performs in wear, heat, corrosive environments and maintains dimensional stability of temperatures up to 2000 degrees F. The valve element 80 is not retained by other components of the flow through pressure regulator 10 and therefore does not share a permanent contact with the valve biasing member 90. The valve element 80 is free to move both axially and radially when displaced from the valve seat 70. Valve biasing member 90 is positioned on the upper surface of the valve element 80 to assist with movement of the valve element 80 in an axial direction away from the valve seat 70. When the pressure of the inlet fuel is greater than the force exerted by the valve biasing member 90, the fuel pushes the valve element 80 in an axial upward direction and the valve element 80 moves from engagement with the valve seat 70. Fuel flows through the flow through pressure regulator 10 until the bias of the valve biasing member 90 is strong enough to return the valve element 80 to the valve seat 70 thus closing the opening in the valve seat 70. Others skilled in the art may wish to select different shapes for the valve element 80 including a truncated sphere or cone. Others skilled in the art may also choose to weld the valve element 80 to the valve biasing member 90.
The flow through pressure regulator 10 also includes a fuel cover 100 that is preferably made of a plastic molded material and generally houses the flow through pressure regulator 10. Fuel cover 100 includes fuel passageway 120 for directing and turning the flow of fuel from the valve biasing member 90 to fuel outlet 130. The fuel outlet 130 is generally circular in shape and located on the outer edge of cover 100. Fuel cover 100 also acts to keep the valve biasing member 90 submerged in fuel at all times during fuel flow which enhances durability of the valve biasing member 90 as well as dampen vibrating noise of the valve biasing member 90. After exiting valve biasing member 90, the fuel builds in the cover chamber 140 above the valve biasing member 90 and climbs over internal wall 150 and then flows to fuel outlet 130. By this process, the flow of fuel exits in an organized flow and does not discharge in various directions. Similarly, submergence of the valve biasing member 90 in the fuel ensures that the fuel is located on both the top portion and the bottom portion of the valve biasing member 90. Submergence of the valve biasing member 90 in fuel also ensures that the fuel is not aerated which consequently lessens noise in the flow through pressure regulator 10. Lastly, the fuel cover 100 protects the valve biasing member 90 during shipping and handling.
As shown in
With reference to
In the preferred embodiment, the plurality of fuel passages 160, 170 are U-shaped channels, however, others skilled in the art may select alternate shapes including oval, rectangular, V, round or slot form. However, at least one passage 170 must have a cross sectional area that is different from that of all the other passages 160. It can be appreciated that the pressure differential creating structure can include a combination of passages 170 that have cross-sectional areas that are different from the cross-sectional areas of passages 160. It is preferred to have the total number of the plurality of fuel passages 160 and 170 to be greater than or equal to 6. It is also preferred to have the plurality of fuel passages tapered top down such that the width on the top is greater than the width on the bottom.
An advantage of the unbalanced fuel tube 30 is that it can be manufactured by adding a secondary operation (e.g., further machining) to the conventional configuration.
The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.
