Dual sump transmission hydraulic control system
AssigneeFord Global Technologies, LLC
InventorDerek Kinch
Life of this patent
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Abstract
A hydraulic control system includes a primary sump and an auxiliary sump. When the transmission fluid is warm, fluid remains in the auxiliary sump reducing the volume of oil in circulation throughout the transmission to reduce parasitic losses. An oil control valve is designed to block flow of oil from the auxiliary sump to the primary sump when the fluid is warm and to allow flow when the fluid is cold. The oil control valve also responds to transmission line pressure. At moderate temperatures, fluid is held in the auxiliary sump when the engine is running but drains back to the primary sump when the engine is off.
Claims21
A hydraulic control system for a transmission comprising:
- a primary sump;
- an auxiliary sump;
- and
- an oil control valve configured to automatically restrict flow of fluid from the auxiliary sump to the primary sump, without a command from an external controller, in response to a temperature of the fluid exceeding a temperature threshold and configured to vary the temperature threshold based on whether an engine is running.
An oil control valve comprising:
- a housing defining first, second, third, and fourth ports;
- a first spool supported to slide within the housing in response to fluid pressure in the first port;
- a second spool supported to slide within the housing and biased toward the first spool by a spring, the second spool configured to permit flow between the second and third ports in a first position towards the first spool and to block flow between the second and third ports in a second position away from the first spool;
- and
- a wax motor configured to separate the first and second spools by a distance that is a function of a temperature of fluid in the fourth port.
A valve comprising:
- first and second sliding spools, the first spool biased toward the second spool by fluid pressure in a first port, the second spool biased toward the first spool by a spring, the second spool configured to alternately block a second port or to fluidly connect the second port to a third port based on axial position;
- and
- a wax motor, thermally connected to a fourth port, separating the first and second spools.
Dependencies are inferred from the claim text.