Leak check for fuel vapor purge system
First Claim
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1. An apparatus of checking a leak in a fuel vapor purge system comprising:
- pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
leak checking means for checking presence or absence of the leak in the fuel vapor purge system based on the pressure of the fuel vapor purge system detected by the pressure checking means when the fuel vapor purge system is maintained in a hermetically closed state; and
erroneous check avoiding means for avoiding an erroneous check caused by a deformation of the fuel tank.
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Abstract
A leak check system executes a leak check processing. In the leak check processing, the system closes a canister valve and a purge valve to close the fuel vapor purge system. Then, the system detects and monitors a pressure in the fuel vapor purge system. During the leak check processing, the system detects a rapid change of the pressure that is caused by a deformation of a wall of a fuel tank. The system cancels or suspends the processing to avoid erroneous detection of the leak. If the leak check is canceled, the system opens the canister valve to open the fuel vapor purge system.
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Citations
13 Claims
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1. An apparatus of checking a leak in a fuel vapor purge system comprising:
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pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
leak checking means for checking presence or absence of the leak in the fuel vapor purge system based on the pressure of the fuel vapor purge system detected by the pressure checking means when the fuel vapor purge system is maintained in a hermetically closed state; and
erroneous check avoiding means for avoiding an erroneous check caused by a deformation of the fuel tank. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus of checking a leak of a fuel vapor purge system comprising:
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pressure detecting means for detecting a pressure of a fuel vapor purge system including a fuel tank;
a first valve for opening and closing an atmosphere communicating path of the fuel vapor purge system;
leak checking means for checking presence or absence of a leak of the fuel vapor purge system based on the pressure detected by the pressure detecting means when at least the first valve is closed to thereby maintain the fuel vapor purge system in a closed state when the engine is stopped; and
means for opening the first valve when finishing the leak check.
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11. An apparatus of checking a leak of a fuel vapor purge system which is a fuel vapor purge system for purging fuel vapor generated by evaporating a fuel in a fuel tank to an intake system of an engine, said apparatus comprising:
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pressure detecting means for detecting a pressure of the fuel vapor purge system including the fuel tank;
a first valve for opening and closing an atmosphere communicating path of the fuel vapor purge system;
leak checking means for checking presence or absence of a leak of the fuel vapor purge system based on the pressure detected by the pressure detecting means when at least the first valve is closed to thereby maintain the fuel vapor purge system in a hermetically closed state in stopping to operate the engine; and
valve controlling means for temporarily releasing the hermetically closed state of the fuel vapor purge system by temporarily opening the first valve after finishing to check the leak and thereafter closing the first valve again. - View Dependent Claims (12, 13)
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Specification