Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
1999-08-31
2001-10-16
Yuen, Henry C. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C123S468000
Reexamination Certificate
active
06302088
ABSTRACT:
BACKGROUND OF THE INVENTION
1 . Field of the Invention
This invention relates to a fuel injector mounting construction for an in internal combustion engine, and more particularly to an improved fuel injector mounting construction on a direct injected engine that can securely hold a fuel injector notwithstanding manufacturing tolerances.
2. Description of Related Art
In all fields of engine design, there is an increasing emphasis on obtaining more effective emission control, better fuel economy and, at the same time, continued high power output. This trend has resulted in the substitution of fuel injection systems for carburetors as the engine charge former. In the common systems used, fuel is injected into an intake air manifold. In order to obtain still further improvement, direct injection systems are being considered. These systems inject fuel directly into the combustion chamber and thus have significant potential advantages such as fine emission control.
An injection nozzle of a fuel injector employed in a conventional direct injection system is exposed to a combustion chamber through an opening formed in a cylinder head assembly. A forked member usually is used to affix the fuel injector onto the cylinder head assembly. The forked member is secured to the cylinder head assembly with a fastener such as a bolt. Meanwhile, the forked member contacts the body of the fuel injector with its forked section to push a flange of the fuel injector toward the combustion chamber so that the injection nozzle of the fuel injector can be exposed to the combustion chamber.
The fuel injector often has a mount section between the flange and the injection nozzle. This mount section has a diameter larger than a diameter of the injection nozzle but smaller than a diameter of the flange.
The cylinder head opening includes two sections: a small diameter opening section and a large diameter opening sections. A generally square step occurs at the transition between the two opening sections.
The mount section of the fuel injector is seated at this step portion and loaded by the forked member. A seal member, such as a disc spring, conventionally is provided between the mount section of the fuel injector and the step portion to seal up this area.
On occasion, the loading on the fuel injector and thus on the seal can be non-uniform around the seal and can be less than a desired loading. The effectiveness of the seal thus is jeopardized. This occurs because the configuration of the forked member and the surface of the cylinder head on which it is mounted vary due to manufacturing tolerances. If these tolerances stack-up adversely, the forked member does not squarely load the fuel injector, and thus the loading around the seal is not uniform. At the extreme, the fuel injector can assume a noticeably skewed orientation relative to a central axis of the opening in which is mounted.
Hot gases and flames can leak through the seal if the fork member does not properly load the fuel injector and compress the seal. That is, if the seal is not uniform and one section of the seal is not properly compressed, hot gases and flames will leak through the improperly loaded section of the seal. The injector nozzle consequently is excessively heated and deposits can form on the nozzle. These deposits can block and clog the nozzle apertures thereby preventing proper fuel injection and effecting engine performance and emission control.
SUMMARY OF THE INVENTION
A need therefore exists for a mounting construction of the fuel injector that consistently produces an effective seal between fuel injector and the engine body.
In accordance with one aspect of the present invention, a direct fuel injected, internal combustion engine comprises an engine body defining, at least in part, at least one combustion chamber. A fuel injector is arranged to spray fuel directly into the combustion chamber. The engine body has an opening through which the fuel injector is inserted, and the fuel injector having a contact surface. A thrust member is arranged to exert a loading onto the contact surface toward the combustion chamber, and a fixing member affixes the thrust member onto the engine body. A sealing member is disposed within a space between the fuel injector and the opening. The thrust member includes a thrust section contacting the contact surface of the fuel injector and a fixing section at which the thrust member is affixed onto the engine body by the fixing member. At least one of the thrust section and the fixing section having a convex surface.
The convex surface allows for varying orientations of the thrust member relative to the engine body when mounted to the engine body. The thrust member in this manner can squarely load the fuel injector contact surface such that the applied force is substantially uniform about the contact surface despite manufacturing tolerance stack-ups. The generally uniform pressure about the contact surface at a desired loading produces uniform pressure about the sealing member to produce an effective seal between the fuel injector and the engine body, thereby inhibiting overheating of the fuel injector and deposit formations on a fuel injector nozzle.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.
REFERENCES:
patent: 4203402 (1980-05-01), Freyn
patent: 4206725 (1980-06-01), Jenkel et al.
patent: 4829646 (1989-05-01), Cigolotti et al.
patent: 4938193 (1990-07-01), Raufeisen et al.
patent: 5566658 (1996-10-01), Edwards et al.
Gimie Mahmoud
Knobbe Martens Olson & Bear LLP
Sanshin Kogyo Kabushiki Kaisha
Yuen Henry C.
LandOfFree
Fuel injector mounting construction for engine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fuel injector mounting construction for engine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fuel injector mounting construction for engine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2597794