Leak diagnosis device
First Claim
1. A leak diagnosis device comprising:
- a diagnosing device for performing leak diagnosis of determining whether a leak hole is formed in a purge device, which adsorbs fuel vapor generated in a fuel tank with an adsorbent in a canister and purges the fuel vapor adsorbed by the adsorbent into an intake passage of an internal combustion engine;
a state sensing device, when the fuel vapor adsorbed by the adsorbent separates from the adsorbent and produces a mixture gas, for sensing a state of the fuel vapor in the mixture gas; and
a period calculating device for causing the state sensing device to perform the state sensing multiple times from a period in which the pressure in the purge device increases due to generation of the fuel vapor after an operation of the engine is stopped and for calculating a state stabilization period in which a change of the fuel vapor state becomes equal to or less than a reference value based on the result of the multiple times of the state sensing, wherein the diagnosing device performs the leak diagnosis in the state stabilization period calculated by the period calculating device.
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Accused Products
Abstract
Concentration measurement is performed multiple times from a period in which pressure in a purge device increases due to generation of fuel vapor after operation of an engine is stopped. A concentration stabilization period, in which a change in the fuel vapor concentration is equal to or less than a reference value, is calculated based on results of the multiple times of the concentration measurement. Leak diagnosis is performed during the concentration stabilization period. As a result, even if a period for the pressure in the purge device to stabilize fluctuates due to an environment in which a vehicle is located, the leak diagnosis can be performed immediately when the pressure in the purge device stabilizes and a state suitable for the leak diagnosis is reached.
23 Citations
7 Claims
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1. A leak diagnosis device comprising:
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a diagnosing device for performing leak diagnosis of determining whether a leak hole is formed in a purge device, which adsorbs fuel vapor generated in a fuel tank with an adsorbent in a canister and purges the fuel vapor adsorbed by the adsorbent into an intake passage of an internal combustion engine;
a state sensing device, when the fuel vapor adsorbed by the adsorbent separates from the adsorbent and produces a mixture gas, for sensing a state of the fuel vapor in the mixture gas; and
a period calculating device for causing the state sensing device to perform the state sensing multiple times from a period in which the pressure in the purge device increases due to generation of the fuel vapor after an operation of the engine is stopped and for calculating a state stabilization period in which a change of the fuel vapor state becomes equal to or less than a reference value based on the result of the multiple times of the state sensing, wherein the diagnosing device performs the leak diagnosis in the state stabilization period calculated by the period calculating device. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A leak diagnosis method of performing leak diagnosis of determining whether a leak hole is formed in a purge device, which adsorbs fuel vapor with an adsorbent, the leak diagnosis method comprising the steps of:
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sensing a state of the fuel vapor in a mixture gas produced by the fuel vapor separating from the adsorbent; and
calculating a state stabilization period in which a change of the state of the fuel vapor is equal to or less than a reference value based on the result of multiple times of the sensing, wherein the leak diagnosis is performed in the state stabilization period.
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Specification