US 5,873,349 AGranted

Fuel pressure regulator

AssigneeWalbro Corporation

InventorsCharles H. Tuckey, G. Clarke Oberheide

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Abstract

For a fuel injected combustion engine a fuel pressure regulator having a rapidly and accurately regulated output pressure over a wide range of flow rates by bypassing and returning to a fuel tank a portion of the input fuel from a fuel pump through a bypass valve actuated by a flexible diaphragm. The diaphragm is responsive to the pressure of the input fuel on one side of the diaphragm and a vacuum on the other side of the diaphragm having a magnitude which is varied as a function of the flow rate of the fuel bypassed through the valve and returned to the fuel tank. Preferably, this vacuum is produced by a venturi or orifice through which the bypass fuel flows. Applying this vacuum to the diaphragm opposes the bias of a spring acting on the diaphragm and provides an output fuel pressure to the engine over a wide range of flow rates which is essentially constant relative to the atmosphere or, if desired, an output fuel pressure having a positive slope which increases with increasing flow rate of the output fuel supplied to the engine.

Claims20

Dependent claims

A fuel pressure regulator of the pressure of fuel downstream of the regulator comprising a housing, a fuel flow passage in the housing having a fuel inlet to receive fuel and a fuel outlet to discharge fuel downstream of the regulator, a bypass passage in the housing communicating with the exterior of the housing and selectively communicating with the fuel flow passage, a diaphragm of a flexible elastomeric material carried by the housing and having a pair of generally opposed faces with at least a portion of one face continuously communicating with the fuel flow passage and the elastomeric one face itself providing a closure for a valve seat, a valve seat communicating with the bypass passage and the closure of the one face of the diaphragm being yieldably biased toward a closed position on the seat and actuated by the diaphragm to vary and control the rate of fuel flow through the bypass passage and to the exterior of the housing, a restricted orifice communicating with the bypass passage downstream of the valve seat and communicating with at least a portion of the other side of the diaphragm to apply a partial vacuum thereto when fuel flows through the bypass passage and the restricted orifice to bias the diaphragm toward the fully open position of the valve closure, and the restricted orifice and diaphragm are constructed and sized to regulate the pressure of fuel downstream of the regulator to a pressure which is one of substantially constant or increasing with increasing flow rate of fuel downstream of the regulator over a wide range of downstream fuel flow rates.

Dependencies are inferred from the claim text.