Methods and systems for fuel vapor metering via voltage-dependent solenoid valve on duration compensation
First Claim
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1. A method for an engine comprising:
- during fuel vapor purging, applying a signal to an electronically controllable solenoid valve coupling a fuel vapor canister and an intake manifold of the engine in synchronization with a crankshaft position;
a pulse width of the signal adjusted differently, based on an offset duration determined based on an instantaneous system voltage, depending on a comparison of an opening response time of the solenoid valve to a closing response time of the solenoid valve.
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Abstract
Methods and systems are provided for compensating a pulse width of a signal applied to a solenoid purge valve based on an input voltage, and delays in opening and/or closing the solenoid valve.
31 Citations
20 Claims
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1. A method for an engine comprising:
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during fuel vapor purging, applying a signal to an electronically controllable solenoid valve coupling a fuel vapor canister and an intake manifold of the engine in synchronization with a crankshaft position; a pulse width of the signal adjusted differently, based on an offset duration determined based on an instantaneous system voltage, depending on a comparison of an opening response time of the solenoid valve to a closing response time of the solenoid valve. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for an engine including a solenoid canister purge valve coupling a fuel vapor canister and an intake manifold of the engine comprising:
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during a first condition, decreasing a pulse width of a signal applied to the solenoid valve based on a desired purge volume, a first purge flow rate, and a decreased offset duration; during a second condition, increasing the pulse width of the signal based on the desired purge volume, a second purge flow rate, and the decreased offset duration. - View Dependent Claims (13, 14, 15, 16, 17)
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18. An engine system comprising:
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an engine including an intake manifold; a fuel tank; a fuel vapor canister coupled to the fuel tank; a canister purge valve coupled between the intake manifold and the canister for injecting stored fuel vapors from the canister to the intake; and a controller with computer readable instructions for; during purging conditions, determining a first duty cycle of a signal delivered to the valve for purging the canister based on a desired purge volume and a purge flow rate; determining an offset duration based on an instantaneous system voltage; adding the offset duration to the first duty cycle to obtain a second duty cycle of the signal if a solenoid opening response time is greater than a solenoid closing response time; subtracting the offset duration from the first duty cycle to obtain a third duty cycle of the signal if the solenoid opening response time is less than the solenoid closing response time; and delivering the signal in synchronization with an engine crankshaft position. - View Dependent Claims (19, 20)
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Specification