Heat seal for fuel injection nozzles

Claim 1

Apparatus comprising: an internal combustion engine having at least one cylinder, including a combustion chamber; at least a first bore hole extending from within said at least one cylinder and combustion chamber outwardly thereof; at least a second bore hole coaxially and longitudinally outwardly extending with respect to said first bore hole, said second bore hole having a diameter greater than the diameter of said first bore hole thereby forming a radially offset shoulder at the interface of said first bore hole with said second bore hole; a fuel injection nozzle disposed in close proximity within said at least first and second bore holes; an elongate annular volume adjacent to said combustion chamber being defined by said radially offset shoulder, an internal surface of said second bore hole and an external surface of said fuel injection nozzle, said annular volume adjacent to said combustion chamber having an axial length substantially greater than the radial distance between said internal surface of said second bore hole and said external surface of said fuel injection nozzle; an elongate generally cylindrical seal member disposed about the fuel injection nozzle, said seal member having an axial length substantially greater than the radial wall thickness thereof to substantially fill, in a relaxed condition, said elongate annular volume; said elongate generally cylindrical seal member consisting of a firm but pliable heat resistance substance; said seal member being operably axially compressible; and means for expanding said seal member to radially and axially completely fill said annular volume adjacent to said combustion chamber and forcing said seal member to radially abut against the surfaces defining the radial extent of said annular volume thus preventing hot combustion gases from entering said elongate annular volume.