Swellable adsorbent diagnostic for fuel vapor handling system
First Claim
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1. An evaporative emission control system comprising:
- a fuel vapor storage canister;
a swellable material within the canister expandable and contractible in response to changes in the concentration of fuel vapor in the canister; and
a sensor positioned adjacent to the swellable material, wherein the expansion and contraction of the swellable material in response to changes in fuel vapor concentration as detected by the sensor is used to aid in diagnosing the system.
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Abstract
An apparatus and method for use in diagnosing an evaporative emission canister collection and purge system. An EVAP system of a vehicle can be diagnosed through the use of a swellable adsorbent disposed in the system'"'"'s canister. The swellable adsorbent is expandable upon adsorption of fuel vapors and contractible upon desorption. By sensing the expansion and contraction response, a diagnostic mechanism can determine whether the vapor collection and purge functions are operating properly.
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Citations
9 Claims
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1. An evaporative emission control system comprising:
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a fuel vapor storage canister; a swellable material within the canister expandable and contractible in response to changes in the concentration of fuel vapor in the canister; and a sensor positioned adjacent to the swellable material, wherein the expansion and contraction of the swellable material in response to changes in fuel vapor concentration as detected by the sensor is used to aid in diagnosing the system. - View Dependent Claims (2, 3)
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4. An evaporative emission control system that receives fuel vapor from a vehicle'"'"'s fuel system and releases stored fuel vapor to the vehicle'"'"'s engine induction system comprising:
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a fuel vapor storage canister; swellable adsorbent within the canister, the swellable adsorbent expandable upon adsorption of fuel vapor and contractible upon release of fuel vapor; a vapor collection system to transfer fuel vapor to the canister; a purge system to transfer fuel vapor from the canister to the engine induction system; and a sensor detecting expansion and contraction of the adsorbent material to aid in diagnosing whether the vapor collection system and the purge system are operating correctly. - View Dependent Claims (5, 6)
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7. An evaporative emission control system for a vehicle having an engine and a fuel system with a fuel tank containing fuel comprising:
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a fuel vapor storage canister including; swellable adsorbent expandable upon adsorption of fuel vapor and contractible upon release of fuel vapor; and a sensor adjacent to the swellable adsorbent; and a diagnostic system to determine whether the evaporative emission control system is operating correctly by performing a multiple part diagnostic test including; means responsive to a first signal from the sensor that the swellable adsorbent is expanded for determining whether the evaporative emission control system is functioning correctly; and means responsive to a second signal from the sensor that the swellable adsorbent is contracted for determining whether the evaporative emission control system is operating correctly.
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8. An evaporative emission control system for a vehicle having an engine and a fuel system with a fuel tank containing fuel comprising:
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a fuel vapor storage canister including; swellable adsorbent expandable upon adsorption of fuel vapors and contractible upon release of fuel vapors contained in the canister; and an expansion sensor adjacent to the swellable adsorbent; a vapor collection system to transfer fuel vapor emitted by the fuel system to the canister; a purge system to selectively transfer fuel vapors from the canister to the engine; a fuel tank level gauge; a fuel temperature sensor; an ambient air temperature sensor; and a diagnostic system to determine whether the evaporative emission control system is operating correctly by performing a multiple part diagnostic test including; means responsive to a first signal from the expansion sensor that the swellable adsorbent is expanded for analyzing the evaporative emission control system including means for waiting a sufficient time to estimate that the canister is purged and means for determining if the sensor indicates that the swellable adsorbent is contracting; and means responsive to a second signal from the sensor that the swellable adsorbent is contracted for analyzing the evaporative emission control system including means for stopping the purge system and means for evaluating input from the fuel tank level gauge, the fuel and ambient air temperature sensors, the expansion sensor and the engine to determine whether the vapor collection system is operating correctly.
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9. A method of diagnosing a fuel vapor emission control system having a canister containing a material expandable and contractible in response to changes in fuel vapor concentration and a sensor responsive to expansion and contraction of the material comprising the steps of:
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reading the sensor; and determining whether the sensor reading is indicative of an expanded condition of the material corresponding to a vapor loaded condition or a contracted condition of the material corresponding to a vapor unloaded condition.
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Specification