Method and system for adjusting a fuel tank isolation valve
First Claim
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1. A method, comprising:
- adjusting a fuel tank isolation valve (FTIV) of a fuel system by sending electrical pulses to the FTIV;
counting each of the electrical pulses to track a position of the FTIV; and
using a canister temperature to verify the position of the FTIV when the position of the FTIV is unknown or invalid.
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Abstract
Methods and systems are provided for adjusting and diagnosing a position of a fuel tank isolation valve (FTIV) of a fuel system. In one example, a method comprises adjusting a FTIV of a fuel system by sending an electrical pulse to the FTIV; and comparing a current draw of the FTIV to a known current draw profile to verify the position of the FTIV. In this way, the position of the FTIV may be diagnosed, thereby resulting in increased accuracy of subsequent valve control.
28 Citations
7 Claims
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1. A method, comprising:
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adjusting a fuel tank isolation valve (FTIV) of a fuel system by sending electrical pulses to the FTIV; counting each of the electrical pulses to track a position of the FTIV; and using a canister temperature to verify the position of the FTIV when the position of the FTIV is unknown or invalid. - View Dependent Claims (2, 3, 4)
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5. A fuel system, comprising:
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an engine; a fuel tank; a canister for storing fuel vapors; a fuel tank isolation valve (FTIV) coupled in a vapor line between the fuel tank and the canister, the FTIV held in both opened and closed positions without any applied current; a controller with computer readable instructions for diagnosing a position of the FTIV and subsequently adjusting the FTIV based on the diagnosed position and engine operating conditions; and a temperature sensor coupled to the canister, and wherein diagnosing the position of the FTIV includes setting a known position of the FTIV as an open position when a temperature of the canister increases above a threshold temperature within a time duration. - View Dependent Claims (6, 7)
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Specification