Cooling fan assisted engine-off natural vacuum test
First Claim
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1. A method for a vehicle fuel system, comprising:
- during an engine-off condition, including an ambient temperature within a threshold range, operating a cooling fan to increase a fuel tank vacuum including operating the cooling fan for a first test duration, the first test duration based on an amount of stored battery charge; and
indicating leaks in the vehicle fuel system based on the increased vacuum.
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Abstract
A method for a vehicle fuel system, comprising: during an engine-off condition, including an ambient temperature within a threshold range, operating a cooling fan to increase a fuel tank vacuum; and indicating leaks in the vehicle fuel system based on the increased vacuum. In this way, an EONV test may be run at mild ambient temperatures which would not otherwise result in the development of adequate fuel tank vacuum to pass the EONV test.
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Citations
17 Claims
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1. A method for a vehicle fuel system, comprising:
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during an engine-off condition, including an ambient temperature within a threshold range, operating a cooling fan to increase a fuel tank vacuum including operating the cooling fan for a first test duration, the first test duration based on an amount of stored battery charge; and indicating leaks in the vehicle fuel system based on the increased vacuum. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for a vehicle fuel system, comprising:
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sealing a fuel tank and monitoring a fuel tank pressure after an engine-off event; and in response to a change in fuel tank pressure during a monitoring period being less than a fuel tank pressure threshold, unsealing the vehicle fuel system and allowing the fuel tank pressure to equilibrate to atmospheric pressure; assessing an ambient temperature; in response to the ambient temperature being within a threshold range, sealing the vehicle fuel system; and operating a cooling fan to increase a fuel tank vacuum to identify leaks in the vehicle fuel system. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification