Evaporative emissions testing based on ambient light amount
First Claim
1. A method comprising:
- routing fuel vapors from a fuel tank in a fuel system to an evaporative emissions control system, the fuel system supplying fuel to an engine which propels a vehicle;
conducting an evaporative emissions test diagnostic procedure of the fuel system and the evaporative emissions control system during a vehicle-off condition via sealing the fuel system and the evaporative emissions control system from atmosphere and monitoring pressure in the fuel system and the evaporative emissions control system; and
adjusting timing of the evaporative emissions test diagnostic procedure and waking a controller to conduct the procedure responsive to detection of an ambient light amount based on output from a solar cell configured on an external surface of the vehicle.
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Abstract
Methods and systems are provided for conducting a test for undesired evaporative emissions in a vehicle fuel system and evaporative emissions control system based on diurnal temperature fluctuations. In one example, a method includes maintaining a vehicle controller in a sleep mode, where a sunrise or sunset event as sensed by a solar cell configured on an external surface of the vehicle triggers the controller to an awake mode whereupon the test for undesired evaporative emissions is conducted. In this way, in use monitoring performance completion rates may be improved, undesired evaporative emissions may be reduced, and the test for undesired evaporative emissions may be conducted during both heat gains and heat losses during a diurnal cycle without negatively impacting the main battery supply.
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Citations
19 Claims
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1. A method comprising:
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routing fuel vapors from a fuel tank in a fuel system to an evaporative emissions control system, the fuel system supplying fuel to an engine which propels a vehicle; conducting an evaporative emissions test diagnostic procedure of the fuel system and the evaporative emissions control system during a vehicle-off condition via sealing the fuel system and the evaporative emissions control system from atmosphere and monitoring pressure in the fuel system and the evaporative emissions control system; and adjusting timing of the evaporative emissions test diagnostic procedure and waking a controller to conduct the procedure responsive to detection of an ambient light amount based on output from a solar cell configured on an external surface of the vehicle. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for a vehicle, comprising:
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routing fuel vapors from a fuel tank in a vehicle fuel system to an evaporative emissions control system which is coupled to atmosphere, the fuel tank supplying fuel to an engine which propels a vehicle; responsive to an indication of a vehicle-off event;
in a first condition, maintaining a controller of the vehicle awake and conducting an engine off natural vacuum (EONV) test of the fuel system and the evaporative emissions control system; and
, in a second condition, sleeping the controller and searching for an indicated change in ambient light amount greater than a threshold;waking the sleeping controller when the indicated change in ambient light amount is greater than a threshold; and conducting an evaporative emissions test diagnostic procedure of the fuel system and the evaporative emissions control system in response to the waking of the controller. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A system for a vehicle, comprising:
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one or more solar cell(s) configured on an external surface of the vehicle; an operational amplifier comparator circuit configured to receive non-inverting input from the one or more solar cell(s), and configured to receive inverting input from a voltage source coupled to a first resistor and a second resistor in series; an edge detector circuit configured to receive a first output voltage from the operational amplifier comparator circuit; a wake module of a controller of the vehicle configured to receive output from the edge detector circuits; a fuel tank configured within a fuel system; a fuel vapor canister, configured within an evaporative emissions control system, coupled to the fuel tank, further coupled to an engine intake via a canister purge valve, and further coupled to atmosphere via a canister vent valve; and a fuel tank pressure transducer; wherein the controller stores computer readable instructions in non-transitory memory that, when executed, cause the controller to; at a vehicle-off event and based on a heat rejection index for an engine run time duration prior to the vehicle-off event, in a first condition, maintain the controller in an awake mode and conduct an engine-off natural vacuum (EONV) test by sealing the fuel system and the evaporative emissions control system from atmosphere via commanding closed the canister vent valve and the canister purge valve, and monitoring pressure in the fuel system and the evaporative emissions control system via the fuel tank pressure transducer; and in a second condition, sleep the controller and, responsive to the wake module of the controller receiving output from the edge detector circuit while the controller is asleep, wake the controller and conduct an evaporative emissions test diagnostic procedure by sealing the fuel system and the evaporative emissions control system from atmosphere via commanding the canister vent valve and the canister purge valve closed and monitoring the pressure in the fuel system and the evaporative emissions control system via the fuel tank pressure transducer. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification