Patent Application
20140311597
The invention relates to fuel supply systems and, more particularly, to a compact flow-through fuel pressure regulator for controlling the pressure of fuel within the fuel system.
Most modem automotive fuel systems use fuel injectors to deliver fuel to the engine cylinders for combustion. The fuel injectors are mounted on a fuel rail to which fuel is supplied 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 by using a pressure regulator that controls the pressure of the fuel in the system at all engine RPM levels.
Conventional flow-through fuel pressure regulators typically include diaphragms. While such pressure regulators have been proven satisfactory, they require either a great number of parts or large parts and thus do not have a small packaging envelope.
Thus, there is a need to provide an improved fuel pressure regulator with fewer and smaller parts than conventional regulators to reduce the material, manufacturing costs thereof, and packaging envelope.
An object 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 a flow-through pressure regulator that includes housing structure having a fuel inlet and a fuel outlet. A seal band is defined by the housing structure. A valve element is movable between open and closed positions. The valve element has a sealing surface that engages the seal band in the closed position to prevent fuel from passing from the fuel inlet to the fuel outlet. A compression spring is disposed in the housing structure. The spring is constructed and arranged to bias the valve element to the closed position in opposition to pressure exerted on the valve element by fuel at the fuel inlet. A guide member is associated with the valve element and is constructed and arranged to align the valve element with respect to the seal band. A calibration member is associated with an end of the spring and is constructed and arranged to pre-set compression of the spring.
In accordance with another aspect of an embodiment, a flow-through pressure regulator includes housing structure having a fuel inlet and a fuel outlet. A seal band is defined by the housing structure. A valve element is movable between open and closed positions. The valve element has a sealing surface that engages the seal band in the closed position to prevent fuel from passing from the fuel inlet to the fuel outlet. A compression spring is disposed in the housing structure. The spring is constructed and arranged to bias the valve element to the closed position in opposition to pressure exerted on the valve element by fuel at the fuel inlet. Means, associated with the valve element, are provided for aligning the valve element with respect to the seal band. Means, associated with an end of the spring, are provided for pre-setting a compression of the spring.
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:
Referring to
The seal band 18 is an annular surface area that is characterized by a surface finish with a minimal amount of leak paths. The metal seal band 18 provides a uniform surface for the metal valve element 22 to selectively interact with the housing structure 12. By achieving contact across the entire seal band 18 a liquid-tight seal is achieved. The seal band 18 is preferably a concave annular surface, coined into the housing structure 12 by a forming member or by the valve element 22.
The fuel pressure regulator 10 includes a compression spring 24, preferably a coil spring, that has one end 25 engaging a guide member 26. The spring 24 provides an acting force upon the guide member 26 that engages the valve element 22. The spring force (load) is transferred onto the valve element 22 via engagement with a concave surface 27 of the guide member 26 so that the convex sealing surface 29 of the valve element 22 engages and thus mates with the concave annular surface of the seal band 18 in a closed position of the valve element 22, thereby preventing fuel flow past the seal band 18. The guide member 26 maintains the valve element 22 aligned within the housing structure 12. The valve element 22 can be separate from or encapsulated with the guide member 26. Other methods used to achieve alignment of the valve element 22 and the seal band 18 can include the addition of a lower guide (not shown) that constrains lateral movement of the valve element 22 which may be located at the equator of the spherical valve element 22.
A calibration member or cap 28 is provided in the housing 12 and engages a second end 30 of the spring 24. The calibration cap 28 and the guide member 26 provide locating or centering features for the compression spring 24. Calibration of the fuel pressure regulator 10 is achieved by pre-setting the compression of the spring 24 via a calibration cap 28 that has a press fit, or other similar methods of assembly, with the housing structure 12 at the fuel outlet 32. The housing 12, valve element 22, spring 24, guide member 26 and calibration cap 28 are aligned along a common axis A.
The fuel pressure is maintained at a predetermined level by balancing the force the fuel is exerting on the spring loaded valve element 22 at a predetermined flow rate. Fuel is delivered to the inlet 14 through a filter 34 where the applied pressure causes the valve element 22 to lift off the seal band 18 allowing fuel to pass through the inlet 14 and around the valve element 22. The fuel then is channeled to the outside through the outlet 32 of the housing structure 12. A seal structure for sealing the regulator 10 to a fuel delivery module (not shown) includes an O-ring 36 or similar connection methods including, but not restricted to, press-fits and barbed surface features on the housing structure 12.
Instead of providing a unitary housing structure 12 as in
The pressure regulators 10, 10′, 10″ and 10′″ do not require an elastomer diaphragm. Furthermore, the regulators use a compact, simple coil spring instead of the large disk springs of conventional regulators and thus are more compact and less expensive to manufacture than conventional regulators.
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.
