Power plants – Fluid motor means driven by waste heat or by exhaust energy... – With supercharging means for engine
Reexamination Certificate
1999-09-30
2001-08-07
Denion, Thomas (Department: 3748)
Power plants
Fluid motor means driven by waste heat or by exhaust energy...
With supercharging means for engine
C415S163000, C415S164000, C092S033000, C092S136000
Reexamination Certificate
active
06269642
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the field of turbochargers having variable turbine inlet geometries. More particularly, the present invention provides a simplified structural arrangement for positioning multiple aerodynamic vanes in the inlet nozzle of the turbine housing and an integrated actuator for control of the vane position.
2. Description of the Related Art
In a turbocharger it is often desirable to control the flow of exhaust gas into the turbine to improve the efficiency or operational range. Various configurations of variable nozzles have been employed to control the exhaust gas flow. Multiple pivoting vanes annularly positioned around the turbine inlet and commonly controlled to alter the throat area of the passages between the vanes is an approach which has been successfully used in prior turbochargers. Various approaches to this method for implementing a variable nozzle are disclosed in U.S. Pat. No. 4,679,984 to Swihart et al. entitled “Actuation System for Variable Nozzle Turbine” and U.S. Pat. No. 4,804,316 to Fleury entitled “Suspension for the Pivoting Vane Actuation Mechanism of a Variable Nozzle Turbocharger” having a common assignee with the present application.
While multiple vane variable nozzle turbochargers have significantly increased the overall efficiency and capability of turbochargers, the complexity of support and actuation structures for the vanes have increased manufacturing costs and occasionally created maintenance issues. It is therefore desirable to reduce the complexity and parts count of variable nozzle structural arrangements and improve the actuation systems to increase reliability and reduce manufacturing cost for turbochargers employing them.
SUMMARY OF THE INVENTION
A variable geometry turbocharger employing the present invention includes a turbine housing having a standard inlet for exhaust gas and an outlet to the exhaust system of the engine. A volute is connected to the inlet and an integral outer nozzle wall is incorporated in the turbine housing casting adjacent the volute. A center housing is attached to the turbine housing . A center bore in the center housing carries a bearing assembly. A compressor housing having an air inlet and a compressed air outlet is attached to the center housing.
A turbine wheel is carried within the turbine housing and attached to a shaft extending through the center housing, supported by the bearing assembly. The shaft attached to a compressor impeller carried within the compressor housing.
A plurality of vanes having rotation posts extending from a first surface substantially parallel to the outer nozzle wall provide the variable nozzle. The posts are received in circumferentially spaced apertures in the outer nozzle wall. The vanes further have actuation tabs extending from the opposite surface of the vanes. A unison ring is engaged between the center housing and the vanes and has a plurality of profiled slots equal in number to the vanes. The slots are oriented obliquely to a circumference of the unison ring and receive the tabs. The profiled surfaces of the slots engage the substantially flat sides of the tabs on different surfaces during the translation to provide optimum control and wear reduction.
Actuation of the unison ring is accomplished by a radial slot and a crank shaft having a pin engaging the radial slot. The crank shaft is movable continuously from a first position to a second position, causing the pin to translate in the radial slot and impart force perpendicular to the radial slot to urge rotational motion of the unison ring. The rotational motion of the unison ring causes the tabs to traverse the actuation slots from a first end of the slots to a second end of the slots. The oblique orientation of the slots causes a continuously variable rotation of the vanes from a first open position to a second closed position.
An integral hydraulic actuator provides the actuation mechanism for the crank shaft. Mounted in a boss in the center housing, the actuator uses a piston and piston rod attached by a rack and pinion to the crank shaft for position control of the vanes. Hydraulic pressure to operate the piston is provided by a solenoid operated multiport valve with direct feedback through a cam mounted on the crank shaft adjacent the pinion gear.
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patent: 4304171 (1981-12-01), Lang et al.
patent: 4403913 (1983-09-01), Fisker
patent: 4502836 (1985-03-01), Swearingen
patent: 4654941 (1987-04-01), Burdette et al.
patent: 4679984 (1987-07-01), Swihart et al.
patent: 4683805 (1987-08-01), Fejes
patent: 4726744 (1988-02-01), Arnold
patent: 4804316 (1989-02-01), Fluery
patent: 5653419 (1997-08-01), Uchisawa et al.
patent: 731822 A (1955-06-01), None
patent: 358122305A (1983-07-01), None
Arnold Steven Don
Kanigowski Voytek
Martin Steven P.
Slupski Kevin
Allied-Signal Inc.
Denion Thomas
Fischer Felix L.
Trieu Thai-Ba
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