Leak diagnostic method for an evaporative emission control system
First Claim
1. A leak diagnostic method for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine, comprising:
- detecting a pressure inside the evaporative emission control system, which includes the fuel tank;
detecting a fuel level in the fuel tank;
calculating a leak determination threshold value based on the detected fuel level to account for a deformation amount of the fuel tank; and
determining is a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value.
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Abstract
A leak diagnostic apparatus is provided for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine. The leak diagnostic apparatus is basically provided with a pressure detecting device and a leak determining device. The pressure detecting device is configured and arranged to detect a pressure inside the evaporative emission control system, which includes the fuel tank. The leak determining device sets a leak determination threshold value in accordance with a deformation amount of the fuel tank, and determines if a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value.
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Citations
5 Claims
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1. A leak diagnostic method for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine, comprising:
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detecting a pressure inside the evaporative emission control system, which includes the fuel tank; detecting a fuel level in the fuel tank; calculating a leak determination threshold value based on the detected fuel level to account for a deformation amount of the fuel tank; and determining is a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value. - View Dependent Claims (2, 3)
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4. A leak diagnostic method for an evaporative emission control system that purges fuel vapor from an inside of a fuel tank to an intake passage of an internal combustion engine, further comprising:
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detecting a pressure inside the evaporative emission control system, which includes the fuel tank; detecting a fuel level in the fuel tank; detecting an ambient temperature of the evaporative emission control system; calculating a leak determination threshold value based on the detected fuel level and the detected ambient temperature to account for a deformation amount of the fuel tank; and determining if a leak exists by comparing the pressure inside the evaporative emission control system while the evaporative emission control system is sealed to the leak determination threshold value. - View Dependent Claims (5)
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Specification