Internal-combustion engines – Charge forming device – Fuel flow regulation between the pump and the charge-forming...
Reexamination Certificate
1999-01-19
2001-02-27
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel flow regulation between the pump and the charge-forming...
C123S470000
Reexamination Certificate
active
06192870
ABSTRACT:
This invention relates to a fuel injector, and in particular to a fuel injector incorporating a filter arrangement for use in removing particulate contaminants from a flow of fuel. The fuel injector may take the form of a pump injector.
It is known to provide a fuel filter in a fuel system for a compression ignition internal combustion engine in order to remove particulate contaminants from the fuel to be injected as the presence of such contaminants may result in small openings in the injector becoming blocked, excessive wear or seizure of close fitting guides, or damage to impact surfaces. However, the provision of such filters restricts the rate of supply of fuel, and it may not be possible to supply fuel at a sufficiently high rate to allow efficient operation of, for example, a pump injector which requires fuel to be supplied thereto at a relatively high rate. The provision of such a filter may also increase the dimensions of the injector which can give rise to problems, for example, where the injector is intended for use in an engine having four or more inlet/exhaust valves.
According to the present invention there is provided a fuel injector comprising first and second housing parts, the first housing part being located within a bore formed in the second housing part, the housing parts defining therebetween an inlet chamber, a delivery chamber axially spaced from the inlet chamber and a filtration flow path communicating with both the inlet chamber and the delivery chamber to filter fuel flowing from the inlet chamber to the delivery chamber.
The inlet chamber, the delivery chamber and the filtration flow path are each conveniently of annular form, the filtration flow path being defined by a clearance between the first and second housing parts.
The first and second housing parts may comprise the spring housing and the cap nut of the injector housing.
By using a clearance between two existing parts of the injector housing as the filtration flow path, a filter arrangement can be provided in an injector without significantly increasing the dimensions of the injector.
Preferably, the injector includes at least one further inlet chamber, at least one further delivery chamber, and independent filtration flow paths between respective pairs of inlet and delivery chambers.
Such an arrangement is advantageous in that a greater fuel flow rate is permitted, the annular flow paths acting, in effect, as two or more filters arranged in parallel.
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Lucas Industries Public Limited Company
Miller Carl S.
Ohlandt Greeley Ruggiero & Perle L.L.P.
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