Abstract: A control module and method for operating the same includes a diurnal control valve module that opens a diurnal control valve (DCV) and an evaporative leak check module (ELCM) diverter valve control module that switches on an ELCM diverter valve. The control module includes a correlation module performs a correlation of a ELCM pressure signal and a fuel tank pressure signal and that generates a fault signal in response to the correlation when the DCV valve is open and the ELCM diverter valve is on.

Abstract: A vehicle fuel emissions system includes a fuel tank, a tank pressure sensor indicating a pressure differential between the tank and a port communicating with the atmosphere, a pump for selectively producing vacuum in the tank, and a passage connecting the pump and a pressure sensor air reference port external to the system.

Abstract: A restriction diagnostic system for a vehicle comprises a pressure difference module and a diagnostic module. The pressure difference module determines a pressure difference between an ambient air pressure and a filtered air pressure measured at a location between an air filter and a valve that is selectively opened to enable ambient airflow through the air filter to a fuel vapor canister. The diagnostic module selectively diagnoses restriction of the airflow through the air filter when the pressure difference is greater than a predetermined pressure.

Abstract: The invention concerns a dual float rollover valve for use in a vehicle fuel tank assembly. The rollover valve may include a housing having an upper portion with a top end defining a vapor passage and an opposed bottom end, and an outer wall extending between the top and bottom ends and defining a channel extending therethrough; and a lower portion having a first end engaging with the bottom end of the upper portion, an opposed second end including a vent hole therethrough, and an outer wall extending between the first end and the second end and defining a chamber therein. An inner seal may be mounted between the channel and the chamber and include a seal bore extending from the channel to the chamber, with an upper float mounted in the channel, and a lower float, mounted in the chamber, having a buoyancy relative to fuel such that it is adapted to float on the fuel and selectively seal against the seal bore.

Abstract: A vehicle fuel emissions system includes a fuel tank, a tank pressure sensor indicating a pressure differential between the tank and a port communicating with the atmosphere, a pump for selectively producing vacuum in the tank, and a passage connecting the pump and a pressure sensor air reference port external to the system.

Abstract: A restriction diagnostic system for a vehicle comprises a pressure difference module and a diagnostic module. The pressure difference module determines a pressure difference between an ambient air pressure and a filtered air pressure measured at a location between an air filter and a valve that is selectively opened to enable ambient airflow through the air filter to a fuel vapor canister. The diagnostic module selectively diagnoses restriction of the airflow through the air filter when the pressure difference is greater than a predetermined pressure.

Abstract: A control module and method for operating the same includes a diurnal control valve module that opens a diurnal control valve (DCV) and an evaporative leak check module (ELCM) diverter valve control module that switches on an ELCM diverter valve. The control module includes a correlation module performs a correlation of a ELCM pressure signal and a fuel tank pressure signal and that generates a fault signal in response to the correlation when the DCV valve is open and the ELCM diverter valve is on.

Abstract: The invention concerns a dual float rollover valve for use in a vehicle fuel tank assembly. The rollover valve may include a housing having an upper portion with a top end defining a vapor passage and an opposed bottom end, and an outer wall extending between the top and bottom ends and defining a channel extending therethrough; and a lower portion having a first end engaging with the bottom end of the upper portion, an opposed second end including a vent hole therethrough, and an outer wall extending between the first end and the second end and defining a chamber therein. An inner seal may be mounted between the channel and the chamber and include a seal bore extending from the channel to the chamber, with an upper float mounted in the channel, and a lower float, mounted in the chamber, having a buoyancy relative to fuel such that it is adapted to float on the fuel and selectively seal against the seal bore.