Internal-combustion engines – Poppet valve operating mechanism – Lubrication
Reexamination Certificate
2000-11-27
2001-10-09
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Lubrication
C123S1950HC, C123S19800E, C123S193500, C123S470000
Reexamination Certificate
active
06298814
ABSTRACT:
TECHNICAL FIELD
This invention relates to a combustion engine rocker arm cover assembly and more particularly to a sectionalized rocker arm cover assembly with protruding fuel injectors.
BACKGROUND OF THE INVENTION
Rocker arm covers are commonly utilized for combustion engine applications. The covers arc engaged sealably over a cylinder head of a combustion engine thereby protecting a series of rocker arms. The covers not only protect the rocker arms, but assure that oil, which sprays about and lubricates the rocker arms and surrounding mechanisms, remains within the engine cylinder head. The rocker arm cover typically is of a one piece construction having a resilient seal placed between the engine cylinder head and the rocker arm cover.
The high-pressure fuel injection system of a diesel combustion engine has a unique configuration compared to that of a gasoline engine. The high-pressure fuel injectors are commonly placed above and parallel to each combustion cylinder and can be accessed after removal of the rocker arm cover. The fuel injectors are fed by high-pressure fuel lines which penetrate a side of the engine cylinder head and engage the fuel injectors perpendicularly at mid-length. This engagement produces numerous problems. First, unwanted lateral stresses are placed upon the injectors which hinder reliability of radially extending injector seals. Second, fuel leakage at the injector connection is not easily detectable. Any leaking fuel can mix with the lubricating oil thereby compounding problems with engine operation.
To resolve these concerns, current interest is to extend the diesel fuel injectors up through the rocker arm cover. Fuel can then be fed to the injectors from a protruding injector end disposed above the rocker arm cover. The high-pressure fuel line connection to the injector is more reliable than the mid-length connection. And, any chance occurrence of fuel leakage is isolated from the engine oil and is easily detectable. Unfortunately, the high-pressure fuel lines must extend over the rocker arm cover to feed the fuel injectors. In order to service the rocker arms or mechanisms beneath the rocker arm cover, the high-pressure fuel lines must be dismantled prior to removing the rocker arm cover.
SUMMARY OF THE INVENTION
The invention provides a sectionalized rocker arm cover assembly having a primary member, a secondary member, a plurality of fuel injectors and a plurality of respective high pressure fuel feed lines. The primary member has a primary brim sealingly connectable to a cylinder head of a combustion engine. Each fuel injector protrudes through an orifice of the primary member. The orifices align longitudinally along the primary member length. Substantially extending longitudinally along the primary member is a primary edge. The primary edge engages sealably to a secondary edge of the secondary member. The secondary member also has a secondary brim sealingly connectable to the cylinder head of the diesel engine. A plurality of high pressure fuel lines extend over the secondary member and connect to a fuel feed end of each fuel injector disposed above the primary member.
Preferably, each orifice of the primary member is defined by an upper edge, a lower edge, and an intermediate surface. The intermediate surface interposes and is defined by the upper and lower edges. Each fuel injector preferably has an extension portion attached beneath the fuel feed end. The extension portion has a shelf facing upward. The cross sectional area of the fuel feed end is smaller than the cross sectional area of the extension portion, the difference amounting to the surface area of the shelf. The shelf contacts the intermediate surface surrounding the primary member orifice. This contact provides vertical support to the primary member thereby providing a reliable seal along the primary and secondary edge of the respective primary and secondary members without the addition of further fasteners. Adequate clearance is provided between the secondary member and the rocker arm mechanisms so that the secondary member can disengage and slide out from beneath the assembled high pressure fuel lines for maintenance of the rocker arms.
Thus, an advantage of the present invention is a reliable seal along the primary and secondary edges.
Another advantage of the present invention is facilitating access below the rocker arm cover without having to dismantle the fuel injection system.
REFERENCES:
patent: 4757789 (1988-07-01), Laine
patent: 5511520 (1996-04-01), Regueiro
patent: 5699770 (1997-12-01), Matsumoto et al.
patent: 5896837 (1999-04-01), Nysten et al.
Keyes Jared
Pearlman Samuel
Detroit Diesel Corporation
Lo Weilun
Panagos Bill C.
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