Apparatus and methods for estimating vehicle fuel composition
First Claim
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1. A method of estimating composition of fuel in the fuel tank of a vehicle, said method comprising:
- detecting a refuel event;
monitoring fuel consumption during a plurality of stages after the refuel event;
determining a plurality of fuel trim shift values relative to the stages; and
using the fuel trim shift values to estimate a fuel composition change.
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Abstract
A method of estimating composition of fuel in the fuel tank of a vehicle. A refuel event is detected. Fuel consumption is monitored during a plurality of stages after the refuel event. A plurality of fuel trim shift values are determined relative to the stages. The fuel trim shift values are used to estimate a fuel composition change. This method eliminates a need for a hardware fuel composition sensor and also provides dynamic filtering of fuel trim values.
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Citations
22 Claims
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1. A method of estimating composition of fuel in the fuel tank of a vehicle, said method comprising:
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detecting a refuel event; monitoring fuel consumption during a plurality of stages after the refuel event; determining a plurality of fuel trim shift values relative to the stages; and using the fuel trim shift values to estimate a fuel composition change. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of estimating composition of fuel in the fuel tank of a vehicle, said method comprising:
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detecting a refuel event; and estimating a change in the fuel composition relative to an amount of fuel consumed after the refuel event, said estimating performed using a fuel trim shift value; said estimating step performed one or more times until said estimated change in the fuel composition approaches or reaches a stable value. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A system for estimating composition of fuel in the fuel tank of a vehicle having an engine, said system comprising:
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means for detecting a refuel event; means for scheduling a plurality of stages after the refuel event based on amounts of fuel consumption; means for monitoring fuel consumption during the stages; means for determining a fuel trim adjustment to control a fuel-air ratio to the engine; and means for estimating a fuel composition change relative to one of the stages using the fuel trim adjustment. - View Dependent Claims (14, 15, 16)
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17. A system for estimating composition of fuel in the fuel tank of a vehicle having an engine, said system comprising a control module that:
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detects a refuel event; and using a fuel trim shift value, estimates a change in the fuel composition relative to an amount of fuel consumed after the refuel event; wherein said control module estimates the change until the estimated change approaches or reaches a stable value. - View Dependent Claims (18, 19)
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20. A method of maintaining closed-loop control of fuel to a vehicle engine at stoichiometry, said method comprising:
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determining a plurality of fuel trim shift values; filtering the fuel trim shift values using a filter having a frequency that changes based on a frequency of an exhaust sensor of the vehicle; and evaluating the filtered fuel trim shift values using an O2 metric based on the exhaust sensor frequency. - View Dependent Claims (21, 22)
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Specification