TECHNICAL FIELD

The present discloser relates to fuel systems for vehicles.

BACKGROUND

Vehicles may include fuel systems that are configured to deliver fuel from a fuel tank to an internal combustion engine.

SUMMARY

A vehicle includes a fuel tank, a canister, a first valve, a second valve, a heater, and a controller. The fuel tank is configured to store fuel. The canister is in fluid communication with the fuel tank and is configured to receive and store evaporated fuel from the fuel tank. The first valve is disposed between the fuel tank and the canister. The second valve is disposed between the canister and ambient surroundings. The heater is disposed within the canister. The controller is programmed to, periodically initiate a diagnostic test, the diagnostic test including, opening the first valve, closing the second valve, deactivating the heater, and sensing a vapor pressure within the fuel tank. The controller is further programmed to, in response to the vapor pressure being less than a threshold during the diagnostic test, output a signal indicating that the heater is operating properly. The controller is further programmed to, in response to the vapor pressure exceeding the threshold during the diagnostic test, output a signal indicating that the heater is unable to turn off.

A vehicle includes a fuel tank, a canister, a fuel tank vent valve, a canister vent valve, a pressure sensor, an electric heater, and a controller. The fuel tank is configured to store fuel. The canister is in fluid communication with the fuel tank. The canister is also configured to receive evaporated fuel from the fuel tank, store the evaporated fuel via adsorption, and deliver the evaporated fuel to an engine via desorption. The fuel tank vent valve is disposed between the fuel tank and the canister. The fuel tank vent valve is configured to facilitate fuel vapor flow from the fuel tank to the canister when open and to isolate the fuel tank from the canister when closed. The canister vent valve is disposed between the canister and ambient surroundings. The canister vent valve is configured to facilitate fluid communication between the canister and the ambient surroundings when open and to isolate the canister from the ambient surroundings when closed. The pressure sensor is disposed between the canister and the fuel tank and is configured to measure a pressure of the fuel vapor. The electric heater is disposed within the canister and is configured to accelerate desorption. The controller is programmed to periodically initiate a first diagnostic test and periodically initiate a second diagnostic test. The first diagnostic test includes opening the fuel tank vent valve, closing the canister vent valve, and activating the electric heater. The controller is further programmed to, in response to the pressure sensor sensing an increase in the pressure of the fuel vapor exceeding a threshold during the first diagnostic test, output a signal indicating that the electric heater is operating properly. The controller is further programmed to, in response to the pressure sensor sensing the increase in the pressure of the fuel vapor being less than the threshold during the first diagnostic test, output a signal indicating that the electric heater is unable to turn on. The second diagnostic test includes opening the fuel tank vent valve, closing the canister vent valve, and deactivating the electric heater. The controller is further programmed to, in response to the pressure sensor sensing the increase in the pressure of the fuel vapor being less than the second threshold during the second diagnostic test, output a signal indicating that the electric heater is operating properly. The controller is further programmed to, in response to the pressure sensor sensing the increase in the pressure of the fuel vapor exceeding a second threshold during the second diagnostic test, output a signal indicating that the electric heater is unable to turn off.

A vehicle includes a fuel tank, a canister, a first valve, a second valve, a heater, and a controller. The fuel tank is configured to store fuel. The canister is in fluid communication with the fuel tank and is configured to receive and store evaporated fuel from the fuel tank. The first valve is disposed between the fuel tank and the canister. The second valve is disposed between the canister and ambient surroundings. The heater is disposed within the canister. The controller is programmed to, periodically initiate a diagnostic test, the diagnostic test including, opening the first valve, closing the second valve, activating the heater, and sensing the vapor pressure within the fuel tank. The controller is further programmed to, in response to the vapor pressure being greater than a threshold during the diagnostic test, output a signal indicating that the electric heater is operating properly. The controller is further programmed to, in response to the vapor pressure being less than the threshold during the diagnostic test, output a signal indicating that the electric heater is unable to turn on.

