Diagnosis apparatus for fuel vapor purge system and method thereof
First Claim
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1. A diagnosis apparatus for a fuel vapor purge system which traps the fuel vapor generated in a fuel tank to a canister, to purge the fuel vapor trapped to said canister to an intake passage of an internal combustion engine, comprising;
- a pressure generator forcibly changing a pressure in a shielded purge passage inclusive of said fuel tank;
a pressure detector detecting the pressure in said purge passage; and
a diagnosis device forcibly changing the pressure in said purge passage by said pressure generator and also receiving a detection signal from said pressure detector, to diagnose whether or not the leakage occurs in said purge passage, wherein said diagnosis device starts the diagnosis processing from a standby period has elapsed after an operation of said internal combustion engine was stopped.
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Abstract
In a fuel vapor purge system, a diagnosis section inclusive of a fuel tank is pressurized from the generation of fuel vapor in the fuel tank has been finished after an operation of an engine was stopped, and the diagnosis is performed based on a pressure in the diagnosis section.
14 Citations
25 Claims
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1. A diagnosis apparatus for a fuel vapor purge system which traps the fuel vapor generated in a fuel tank to a canister, to purge the fuel vapor trapped to said canister to an intake passage of an internal combustion engine, comprising;
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a pressure generator forcibly changing a pressure in a shielded purge passage inclusive of said fuel tank;
a pressure detector detecting the pressure in said purge passage; and
a diagnosis device forcibly changing the pressure in said purge passage by said pressure generator and also receiving a detection signal from said pressure detector, to diagnose whether or not the leakage occurs in said purge passage,wherein said diagnosis device starts the diagnosis processing from a standby period has elapsed after an operation of said internal combustion engine was stopped. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A diagnosis apparatus for a fuel vapor purge system which traps the fuel vapor generated in a fuel tank to a canister, to purge the fuel vapor trapped to said canister to an Intake passage of an internal combustion engine, comprising:
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pressure generating means for forcibly changing a pressure In a shielded purge passage inclusive of said fuel tank;
pressure detecting means for detecting the pressure in said purge passage; and
diagnosis means for forcibly changing the pressure In said purge passage by said pressure generating means and also receiving a detection signal from said pressure detecting means, to diagnose whether or not the leakage occurs in said purge passage, wherein said diagnosis means starts the diagnosis processing from a standby period has elapsed after an operation of said internal combustion engine was stopped.
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14. A diagnosis method for a fuel vapor purge system which traps the fuel vapor generated in a fuel tank to a canister, to purge the fuel vapor trapped to said canister to an intake passage of an internal combustion engine, comprising the steps of:
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judging whether or not a standby period has elapsed after an operation of said internal combustion engine was stopped;
forcibly changing a pressure in a shielded purge passage inclusive of said fuel tank after said standby period has elapsed;
detecting the pressure in said purge passage; and
diagnosing whether or not the leakage occurs in said purge passage,;
based on the detected pressure. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification