Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1999-11-12
2001-05-15
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C138S030000
Reexamination Certificate
active
06230685
ABSTRACT:
FIELD OF INVENTION
This invention relates to a damper for automotive fuel systems, and more particularly to a damper for minimizing fuel pressure pulsations in a fuel rail.
BACKGROUND OF INVENTION
Existing fuel delivery systems which use an in-tank fuel pressure regulator usually employ an energy absorbing device mounted on or near the fuel rail. The energy absorbing device serves to compensate for fuel pressure pulsations created in the fuel rail that occur as a result of sequential firing of fuel injectors operatively connected to the fuel rail.
A known energy absorbing device is a damper mounted on the fuel rail. A damper of this type is disclosed in commonly-assigned, co-pending U.S. patent application Ser. No. 09/086,084, entitled “Fuel Rail Damper”, filed, May 28, 1998, which is incorporated herein in its entirety by reference. This known damper has an upper chamber and a lower chamber separated by a solid, flexible diaphragm. The upper chamber contains a spring biased against the diaphragm. The lower chamber has an opening which allows fuel to enter from the fuel rail and contact the diaphragm. An upper flange of the lower chamber extends inwardly at an angle to form a radial shoulder, which maximizes an effective area of the diaphragm. Under certain operative conditions, the diaphragm can adhere to the radial shoulder, which substantially reduces the effective area of the diaphragm, and can cause the diaphragm to become non-responsive to pressure pulses. Thus, the radial shoulder, which is employed to maximize the effective area of the diaphragm, can, under certain conditions, actually minimize the operability of the damper.
SUMMARY OF THE INVENTION
The present invention provides a damper for a fuel system having a housing which is separated by a diaphragm into a first chamber and a second chamber. The first chamber is sealed and contains a spring biased toward the diaphragm. The second chamber has an opening to allow fuel from the fuel rail to enter the damper and contact the diaphragm. The second chamber includes a radial shoulder that maximizes the effective area of the diaphragm. A spacer is disposed in the second chamber that prevents the diaphragm from contacting the radial shoulder. The spacer, therefore, maintains the diaphragm in a position which ensures that the maximum effective area of the diaphragm is exposed to fuel in the second chamber. To assist the spacer, a seat, that supports the spring, is disposed in the first chamber, and on the opposite side of the diaphragm from the spacer.
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Bennett Jan L.
Kilgore Jason T.
Robinson Barry S.
Moulis Thomas N.
Siemens Automotive Corporation
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