Hydraulic pump system with reduced cold start parasitic loss
AssigneeCaterpillar Inc.
InventorsBryan E. Nelson, Kirat Shah
Life of this patent
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Abstract
A machine hydraulic pump system including at least one hydraulic pump driven to pressurize hydraulic fluid. A drain port is in fluid communication with an interior lubricating cavity of the pump. A selectively activatable flow control member is in flow-controlling relation to the drain port. The selectively activatable flow control member is adapted to move from a fluid containment condition to a fluid withdrawal condition prior to activation of the pump to at least partially evacuate lubricating liquid from the interior of the pump in response to the temperature of the lubricating liquid dropping below a predefined lower limit.
Claims20
A machine hydraulic pump system, comprising:
- at least one hydraulic pump driven to pressurize hydraulic fluid, said pump including a pump casing defining an interior cavity adapted to hold a lubricating liquid, said lubricating liquid having a temperature;
- at least one drain port in fluid communication with said interior cavity;
- and
- a selectively activatable flow control member disposed in operative relation to said at least one drain port, said selectively activatable flow control member adapted to move from a fluid containment condition to a fluid withdrawal condition in response to said temperature dropping below a predefined lower limit to at least partially evacuate said lubricating liquid from said interior cavity prior to startup of said at least one pump.
A machine hydraulic pump system, comprising:
- at least one hydraulic pump driven to pressurize hydraulic fluid, said pump including a pump casing defining an interior cavity adapted to hold a lubricating liquid said lubricating liquid having a temperature;
- a lower casing drain line operatively connected to a lower casing drain port in fluid communication with said interior cavity;
- an upper casing drain line operatively connected to an upper casing drain port in fluid communication with said interior cavity, said upper casing drain port being disposed in elevated relation relative to said lower casing drain port;
- a selectively activatable flow control member disposed in flow-controlling relation to said lower casing drain line, said selectively activatable flow control member being adapted to move from a fluid containment condition to a fluid withdrawal condition in response to said temperature dropping below a predefined lower limit to at least partially evacuate said lubricating liquid from said interior cavity prior to startup of said at least one pump.
A method of reducing torque drag during start-up of a hydraulic pump in a machine hydraulic pump system having at least one hydraulic pump driven to pressurize hydraulic fluid, said pump including a pump casing defining an interior cavity adapted to hold a lubricating liquid, said at least one hydraulic pump including at least one drain port in fluid communication with said interior cavity, the method comprising;
- selectively moving a flow control member disposed in flow-controlling relation to said at least one drain port from a fluid containment condition to a fluid withdrawal condition prior to startup of said at least one hydraulic pump to at least partially evacuate said lubricating liquid from said interior cavity;
- starting said at least one hydraulic pump without replacing the lubricating liquid evacuated from said pump casing;
- and
- selectively returning said flow control member to the fluid containment condition subsequent to said lubricating liquid being at least partially evacuated from said interior cavity.
Dependencies are inferred from the claim text.