Internal-combustion engines – Valve – Valve seat relation
Reexamination Certificate
2000-03-30
2001-07-17
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Valve
Valve seat relation
Reexamination Certificate
active
06260531
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a valve seat insert and more particularly, to a valve seat insert which substantially prevents corrosion within an engine cylinder head.
BACKGROUND OF THE INVENTION
Valve seat inserts are used in automotive vehicles and are typically and operatively disposed within the cylinder head of a vehicle engine. Particularly, valve seat inserts are selectively forced or press-fitted into a “pocket” or cavity within the cylinder head and are typically manufactured from a relatively hard, wear-resistant and heat-resistant material, such as a cast or sintered metal material. When operatively installed, the valve seat inserts are effective to provide a seating surface for the engine's valves, thereby allowing the valves to selectively open and close. While these valve seats or valve seat inserts provide a strong and durable seating surface for the engine's valves, they suffer from some drawbacks.
For example and without limitation, one such drawback arises from the press-fit engagement or mating of the valve seat insert within the cavity or pocket of the cylinder head. Particularly, the press-fit mating of the valve seat insert results in the formation of a minute gap or crevice between the “top” or back surface of the cavity and the “top” surface of the valve seat insert, which abuttingly engages the “top” or back surface of the cavity. During operation, liquid or fuel passes into this gap and becomes “trapped” or held within the gap. While this “trapped” or held fuel is relatively benign in traditional or conventional engines which burn fuel containing a relatively low percentage of ethanol, it can cause severe damage to engines which burn fuel containing a relatively high percentage of ethanol.
That is, in engines which burn fuel containing a relatively high percentage of ethanol (e.g., greater than 50% ethanol), the trapped or held fuel may form and/or promote the formation of corrosive acids or byproducts which corrode the cylinder head. Over time, this corrosion can become extremely severe, especially in cylinder heads which are manufactured from an aluminum material or alloy, and will oftentimes break or wear through to the engine's water jacket, thereby causing engine failure.
There is therefore a need for a valve seat insert which overcomes some if not all of the drawbacks of prior valve seat inserts.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a valve seat insert which is adapted for use within a cylinder head and which overcomes at least some of the previously delineated drawbacks of prior valve seat inserts.
It is a second object of the invention to provide a valve seat insert which is adapted for use in combination with a cylinder head and which substantially prevents corrosion of the cylinder head.
It is a third object of the invention to provide a valve seat insert which is adapted for use in combination with a cylinder head and which includes several grooves or passages which allow fluid and/or fuel to pass freely between the cylinder head and the insert, thereby preventing corrosion of the cylinder head.
According to a first aspect of the present invention, a valve seat insert is provided. The valve seat insert is adapted for use within a cylinder head having an amount of fuel and a cavity having a first surface. The valve seat insert is disposed within the cavity and has a second surface which engages the first surface and which includes a plurality of notches which cooperate with the first surface to form a plurality of passages which are effective to substantially prevent fuel from becoming trapped between the first surface and the second surface, thereby substantially preventing corrosion of the cylinder head.
According to a second aspect of the present invention, a method is provided for substantially preventing corrosion of a cylinder head having a valve port which receives an amount of fuel and which includes a cavity having a first surface, and a valve seat insert which is secured within the cavity and which includes a second surface which abuts the first surface. The method includes the step of forming a plurality of notches on the second surface of the valve seat insert, effective to form a plurality of passages between the second surface and the first surface. The plurality of passages is effective to substantially prevent fuel from becoming trapped between the first surface and the second surface, thereby preventing corrosion of the cylinder head.
These and other features, aspects, and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.
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Birtel Peter
Haan Deborah Martha
Kraemer Manfred
Opperman Bradley David
Ford Global Tech. Inc
Ford Global Tech., Inc.
Kamen Noah P.
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