Method of determining a fuel tank vapor flow rate
First Claim
1. A method of learning a flow rate of purge vapors from a fuel tank in an evaporative emissions control system comprising:
- determining a concentration of purge vapor in said evaporative emissions control system;
determining a mass flow rate of purge vapor at a purge valve of said evaporative emissions control system; and
combining said concentration of purge vapor and mass flow rate of purge vapor to yield a fuel tank mass flow rate.
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Abstract
A method is provided for accommodating the purge vapors from an evaporative emission control system of an automotive vehicle. The method includes a means of learning the flow rate of purge vapors from the fuel tank. The fuel tank model uses the output of a strategic adaption routine to learn the tank vapor flow rate. This flow rate is used to maintain fuel to air control under varying air flow and purge flow conditions especially under return-to-idle situations. As such, the fuel to air ratio at the injectors can be controlled under varying air flow and purge flow conditions to improve drivability and emissions.
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Citations
8 Claims
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1. A method of learning a flow rate of purge vapors from a fuel tank in an evaporative emissions control system comprising:
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determining a concentration of purge vapor in said evaporative emissions control system; determining a mass flow rate of purge vapor at a purge valve of said evaporative emissions control system; and combining said concentration of purge vapor and mass flow rate of purge vapor to yield a fuel tank mass flow rate. - View Dependent Claims (2, 3, 4, 5)
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6. A method of learning a flow of purge vapors from a fuel tank in an evaporative emissions control system comprising:
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learning a canister purge vapor loading value; comparing said canister purge vapor loading value to a model of canister loading values; and attributing a difference between said canister purge vapor loading value and said model of canister loading values to said flow of purge vapors from said fuel tank. - View Dependent Claims (7, 8)
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Specification