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US 8,984,872 B2Granted
Hydraulic accumulator fluid charge estimation system and method
AssigneeCaterpillar Inc.
InventorsBryan E. Nelson, Jeremy T. Peterson, Jeffrey L. Kuehn
Life of this patent
Estimating the term…
Abstract
A method for estimating a fluid charge of a hydraulic accumulator includes determining a first accumulator pressure at a first time with a pressure sensor, the first time during accumulator charging; determining a second accumulator pressure at a second time with the pressure sensor, the second time during accumulator charging; determining a first fan speed at the first time; determining a second fan speed at the second time; and estimating the fluid charge of the hydraulic accumulator as a function of the first accumulator pressure, the second accumulator pressure, the first fan speed, and the second fan speed.
Claims20
A method for estimating a fluid charge of a hydraulic accumulator in a hydraulic fan circuit including a primary pump, a motor selectively fluidly connected to the pump, and drivingly connected to a fan, comprising:
- determining, at a microprocessor, a first accumulator pressure at a first time with a pressure sensor, the first time being during accumulator charging,
- determining, at the microprocessor, a second accumulator pressure at a second time with the pressure sensor, the second time being during accumulator charging,
- determining, at the microprocessor, a first fan speed at the first time,
- determining, at the microprocessor, a second fan speed at the second time,
- estimating, at the microprocessor, the fluid charge of the hydraulic accumulator as a function of the first accumulator pressure, the second accumulator pressure, the first fan speed, and the second fan speed, and
- controlling, using the microprocessor, the hydraulic fan circuit based upon said estimating.
3 more elements
A method for estimating a fluid charge of a hydraulic accumulator in a hydraulic fan circuit including a primary pump, a motor selectively fluidly connected to the primary pump, and drivingly connected to a fan, comprising:
- determining, at a microprocessor, periodic accumulator pressures with a pressure sensor during an accumulator charging time period,
- determining, at the microprocessor, periodic fan speeds during the accumulator charging time period,
- estimating, at the microprocessor, the fluid charge of the hydraulic accumulator as a function of the periodic accumulator pressures and the periodic fan speeds, and
- controlling, using the microprocessor, the hydraulic fan circuit based upon said estimating.
1 more element
An accumulator fluid charge estimation system, comprising:
- a hydraulic fan circuit including:
- a primary pump,
- a primary accumulator selectively fluidly connected to the primary pump,
- a fan,
- a motor selectively fluidly connected to the primary pump, and drivingly connected to the fan, a fan speed sensor configured to generate periodic fan speed signals indicative of periodic speeds of the fan, and
- a pressure sensor configured to produce periodic accumulator pressure signals indicative of periodic accumulator pressures at the primary accumulator;
- and
- a microprocessor configured to:
- determine, at the microprocessor, the periodic accumulator pressures with the pressure sensor during an accumulator charging time period,
- determine, at the microprocessor, the periodic fan speeds during the accumulator charging time period,
- estimate, at the microprocessor, a fluid charge of the primary accumulator as a function of the periodic accumulator pressures and the periodic fan speeds during the accumulator charging time period, and
- control, using the microprocessor, the hydraulic fan circuit based upon the estimated fluid charge.
9 more elements
An accumulator fluid charge estimation system, comprising:
- a hydraulic fan circuit including:
- a primary pump,
- a primary accumulator selectively fluidly connected to the primary pump,
- a fan, a motor selectively fluidly connected to the primary pump, and drivingly connected to the fan,
- a fan speed sensor configured to generate a first fan speed signal indicative of a first fan speed at a first time during an accumulator charging period, and a second fan speed signal indicative of a second fan speed at a second time during the accumulator charging period, and
- a pressure sensor configured to produce a first accumulator pressure signal indicative of a first accumulator pressure at the primary accumulator at the first time, and a second accumulator pressure signal indicative of a second accumulator pressure at the primary accumulator at the second time;
- and
- a microprocessor configured to:
- determine, at the microprocessor, the first accumulator pressure at the first time with the pressure sensor, the first time being during the accumulator charging period,
- determine, at the microprocessor, the second accumulator pressure at the second time with the pressure sensor, the second time being during the accumulator charging period,
- determine, at the microprocessor, the first fan speed at the first time,
- determine, at the microprocessor, the second fan speed at the second time,
- estimate, at the microprocessor, a fluid charge of the primary accumulator as a function of the first accumulator pressure, the second accumulator pressure, the first fan speed, and the second fan speed, and
- control, using the microprocessor, the hydraulic fan circuit based upon the estimated fluid charge.
11 more elements
A machine, comprising:
- an engine,
- a hydraulic fan circuit including:
- a primary pump drivingly connected to the engine a primary accumulator selectively fluidly connected to the primary pump,
- a fan positioned to cool the engine,
- a motor selectively fluidly connected to the primary pump, and drivingly connected to the fan, a fan speed sensor configured to generate periodic fan speed signals indicative of periodic speeds of the fan, and
- a pressure sensor configured to produce periodic accumulator pressure signals indicative of periodic accumulator pressures at the primary accumulator;
- a directional control valve configured to control a flow direction of a fluid associated with a supply passage from the primary pump to the motor and with a return passage from the motor to the primary pump, the directional control valve configured to direct the fluid to flow either from the primary pump through the supply passage in a forward direction, or from the primary pump through the return passage in a reverse direction, wherein the directional control valve is moveable between a first position to direct the fluid flowing in the forward direction from the primary accumulator to the return passage, and a second position to direct the fluid flowing in the forward direction from the supply passage to the primary accumulator;
- and
- a microprocessor configured to:
- determine, at the microprocessor, the periodic accumulator pressures with the pressure sensor during an accumulator charging time period,
- determine, at the microprocessor, the periodic fan speeds during the accumulator charging time period,
- estimate, at the microprocessor, a fluid charge of the primary accumulator as a function of the periodic accumulator pressures and the periodic fan speeds during the accumulator charging time period, and
- control, using the microprocessor, the hydraulic fan circuit based upon the estimated fluid charge.
10 more elements
Dependencies are inferred from the claim text.