Method and apparatus for volumetric calibration of liquid flow sensor output signals
AssigneeFord Motor Company
InventorsEdward S. Greene, Eric M. Knight
Life of this patent
Estimating the term…
Abstract
A liquid flow sensor produces output signals which are monitored over a known volume of flowing liquid. That monitored signal value is scaled according to a predetermined volume of liquid to provide a correction factor, whereby the output signal of the flow sensor is continually corrected to provide an expected number of flow sensor pulses per unit volume.
Claims9
A system for calibrating the reproducible accuracy of an electrical output signal produced by a liquid flow sensor that monitors liquid flowing from a storage tank, wherein said storage tank contains a liquid level sensor which produces an electrical output signal having a value corresponding to the sensed level of said liquid, said system comprising:
- means for storing the values of said liquid level electrical output signal at a designated initial level of said liquid in said tank and at a second designated level separated from said initial value by a predetermined volume of liquid added to said tank;
- means for accumulating said electrical signal from said liquid flow sensor over a period of time corresponding to the time that said liquid level sensor output signal value corresponds to sensed levels between said designated levels and outputing an accumulation signal when said level sensor output signal value corresponds to said initial level;
- and
- means for factoring said electrical signal from said liquid flow sensor by an amount corresponding to said accumulation signal to produce a calibrated flow sensor output signal.
A method of calibrating the output signal of a liquid flow sensor when employed in a system which utilizes a liquid storage tank having an outlet connected to said liquid flow sensor and a liquid level sensor located in said tank, wherein said liquid level sensor produces an output signal having a value that varies corresponding to a range of sensed levels of said liquid within said storage tank, comprising the steps of:
- monitoring the output signal of said liquid level sensor;
- storing a first value of said liquid level sensor output signal corresponding to a first level of said liquid within said tank;
- adding a predetermined quantity of liquid to said tank to bring said liquid to a second level within said range, greater than said first level;
- storing a second value of said liquid level sensor output signal corresponding to said second level of said liquid within said tank;
- accumulating a portion of said output signal of said liquid flow sensor over a time period, subsequent of said storing of said second value, defined by the time that said liquid level sensor output signal values corresponding to sensed levels between said second and first levels to produce an accumulated value of said liquid flow sensor output signals corresponding to said predetermined quantity of added liquid flowing through said liquid flow sensor;
- storing said accumulated value;
- and
- subsequently modifying said output signal from said liquid flow sensor in accordance with said accumulated value, to obtain an ideally scaled output signal that is calibrated according to a volumetric reference.
A method of calibrating an output signal of a fuel flow sensor, in series between a fuel storage tank and a fuel consumming engine, according to a known volume of fuel comprising the steps of:
- inhibiting the operation of said engine;
- measuring the level of said fuel in said tank;
- subsequently storing said first measured level value;
- subsequently adding a predetermined volume of fuel to said tank;
- subsequently measuring the level of said fuel in said tank;
- subsequently storing said second measured level value;
- operating said engine;
- continuing to measure the level of said fuel in said tank;
- accumulating said fuel flow sensor output signal whenever said continuing level measurements indicate the leve of fuel in said tank to be below said second stored level value and above said first stored level value;
- terminating the accumulation step, when said continuing level measurements indicate the level of fuel in said tank has reached said first level value, and producing an accumulation value;
- storing and scaling said accumulation value as a calibration factor of the actual output signal from said fuel flow sensor for a predetermined volume of fuel consummed;
- and
- factoring said fuel flow sensor output signal with said calibration factor to produce a calibrated output signal from said fuel flow sensor.
Dependencies are inferred from the claim text.