Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2002-10-11
2004-08-03
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S463000
Reexamination Certificate
active
06769409
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to fuel injection systems and, more particularly, to a fuel injector support assembly mounted to a cylinder head of an engine.
BACKGROUND
Support clamps for fuel injectors are known in the industry. Generally, these clamps mate with the fuel injector and are secured to the cylinder head of an engine using a fastener that extends directly into the deck of the cylinder head. U.S. Pat. No. 4,206,725 (the '725 patent) discloses an example of one such fuel injector clamp. Specifically, the '725 patent describes a fuel injector nozzle that is mounted to a cylinder head of an engine using a clamp. This clamp includes two leg portions that engage the fuel injector nozzle and force the nozzle into place when the clamp is mounted to the cylinder head.
For mounting to the cylinder head, the clamp of the '725 patent relies upon the use of a fastener that extends through the clamp body and directly into the cylinder head. Specifically, the '725 patent discloses a bolt having a threaded shank. To fasten the clamp to the cylinder head, the threaded shank of the bolt is tightened into a complimentary threaded bore located in the cylinder head. The threaded bore in the cylinder head is a dedicated mounting hole because it serves no other function than to mount the support clamp to the cylinder head.
Fuel injector clamps that attach to the cylinder head with a fastener tightened directly into a dedicated mounting hole in the cylinder head may add a structural weakness to the cylinder head. This is notable because there is a trend among engine manufacturers to increase the cylinder pressure during operation of an engine in order to increase the power density of the engine structure. As cylinder pressures increase, a weak point on the cylinder head, namely the area of the cylinder head delimited by the hole for the fuel injector and the dedicated mounting hole for the fuel injector clamp, has an increasing likelihood of failure. Also, the threaded area of the mounting hole itself may fail under the increased load imparted to the threads by the cylinder pressure.
Direct-mount fuel injector clamps also may complicate the design and production of the cylinder head and, therefore, add to fabrication costs. Because these types of fuel injector clamps are mounted directly to the cylinder head, the area of the cylinder head that receives the clamp fastener may be reinforced with added material. Specifically, a boss is added to the cylinder head, and the boss must have a depth sufficient to accept the full length of the threaded bore of the fastener without allowing penetration of the fastener into the cylinder. The inclusion of an additional boss on the cylinder head adds to the cost of the cylinder head.
Additionally, direct-mount fuel injector clamps may lead to a reduction in the cooling efficiency of the engine. Particularly, the additional material on the cylinder head required to accept the fuel injector clamp fastener increases the volume of material that acts as a heat sink and must be cooled. By increasing the volume of material to be cooled, the cooling efficiency of the engine may be reduced.
The present invention solves one or more of the problems associated with known fuel injector support devices.
SUMMARY OF THE INVENTION
One aspect of the present invention includes an engine that has a cylinder head mounted to an engine block using a plurality of cylinder head mounting bolts. A bracket is mounted to the cylinder head using at least one of the cylinder head mounting bolts. A fuel injector clamp attaches to the bracket and retains the fuel injector.
A second aspect of the present invention includes a method of fastening a fuel injector to an engine. This method includes securing a cylinder head to a block of the engine using a plurality of cylinder head mounting bolts. A fuel injector support assembly is mounted to the cylinder head using at least one of the cylinder head mounting bolts, and the fuel injector is secured to the fuel injector support assembly.
A third aspect of the present invention includes a fuel injector support assembly. This assembly includes a bracket that is configured to mate with at least one mounting boss of a cylinder head of an engine. A fuel injector clamp engages a fuel injector.
REFERENCES:
patent: 4206725 (1980-06-01), Jenkel et al.
patent: 5325834 (1994-07-01), Ballheimer et al.
patent: 5566658 (1996-10-01), Edwards et al.
patent: 5699770 (1997-12-01), Matsumoto et al.
patent: 6196194 (2001-03-01), Mitchell
patent: 6269798 (2001-08-01), Takahashi et al.
patent: 6279516 (2001-08-01), Haugen et al.
patent: 6431152 (2002-08-01), Estacio
Evancik Michael Joseph
Schneider Marvin Patrick
Caterpillar Inc
Finnegan Henderson Farabow Garrett & Dunner
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