# US 11,111,867 B1 · Systems and methods for an evaporative emissions control system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,867 B1 - Document ID: US11111867B1 - Status: Granted - Kind: B1 - Application number: 17/088,492 - Filed: 2020-11-03 - Granted: 2021-09-07 - Earliest claimed: 2020-11-03 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Aed Dudar - Web page: https://patentgrep.com/patent/US11111867B1 ## CPC - F02D 41/004: {Control of the valve or purge actuator, e.g. duty cycle, closed loop control of position} - B60K 15/035: characterised by venting means - B60K 15/03504: {adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems} - B60W 50/0097: {Predicting future conditions} - H03K 5/1534: Transition or edge detectors - H03K 5/24: the characteristic being amplitude - B60K 2015/0348: {for returning the fuel from the motor} - B60K 2015/03514: {with vapor recovery means} - B60K 2015/03561: {Venting means working at specific times} - F02D 41/021: {Introducing corrections for particular conditions exterior to the engine (conjoint control of vehicle sub-units for propelling the vehicle B60W30/18)} - F02D 41/042: {for stopping the engine} - F02D 2200/70: said parameters being related to the vehicle exterior - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract Methods and systems are provided for reverse purging in a non-integrated refueling canister only system based on diurnal temperature variation. In one example, a method may include during a vehicle-off condition, in response to an estimated cooling of fuel in a fuel tank, unseal the fuel tank by pulsing a refueling valve (RV) to an open position. The cooling of the fuel may be estimated based on output of a first solar cell. ## Claims ### Claim 1 A method for an engine in a vehicle, comprising: during a vehicle off condition, in response to an estimated cooling of fuel in a fuel tank, opening a refueling valve (RV) to unseal the fuel tank, the estimated cooling of the fuel based on output of a first solar cell. ### Claim 2 (depends on 1) The method of claim 1, further comprising, in response to an estimated warming of the fuel in the fuel tank, closing the RV to seal the fuel tank, the estimated warming based on output of a second solar cell. ### Claim 3 (depends on 1) The method of claim 1, wherein the RV is coupled to a fuel vapor line regulating flow of fuel vapor between the fuel tank and a canister of an evaporative emissions control (EVAP) system. ### Claim 4 (depends on 3) The method of claim 3, wherein upon opening of the RV, air is drawn into the fuel tank via a vent line and the canister, the air desorbing fuel vapor from the canister and routing the desorbed fuel vapor to the fuel tank. ### Claim 5 (depends on 3) The method of claim 3, wherein the opening of the RV and the closing of the RV is carried out via a comparator circuit activated by a controller at an onset of the vehicle off condition in response to a higher than threshold load in the canister, wherein each of the first solar cell and the second solar cell are configured on an external surface of the vehicle. ### Claim 6 (depends on 5) The method of claim 5, wherein the comparator circuit includes a first operational amplifier configured to receive a first non-inverting input from the second solar cell and a first inverting input from a first voltage source coupled to each of a first resistor and a second resistor in series. ### Claim 7 (depends on 6) The method of claim 6, wherein the comparator circuit further includes a second operational amplifier configured to receive a second non-inverting input from the first solar cell and a second inverting input from a second voltage source coupled to each of a third resistor and a fourth resistor in series. ### Claim 8 (depends on 7) The method of claim 7, wherein each of the second resistor and the fourth resistor are variable resistors, and wherein each of the first resistor and the third resistor are fixed resistors. ### Claim 9 (depends on 7) The method of claim 7, wherein values of each of the second resistor and the fourth resistor are set by the controller at the onset of the vehicle off condition based on a level of fuel in the fuel tank, the values of each of the second resistor and the fourth resistor increasing with a decrease in the level of fuel in the fuel tank. ### Claim 10 (depends on 7) The method of claim 7, wherein outputs of each of the first operational amplifier and the second operational amplifier are configured as inputs to an OR logic gate, and an output of the OR logic gate is configured as an input to an edge detector circuit. ### Claim 11 (depends on 10) The method of claim 10, wherein the edge detector circuit includes an exclusive OR (XOR) logic gate, and wherein the RV receives an output of the edge detector circuit. ### Claim 12 (depends on 2) The method of claim 2, wherein the estimated cooling of the fuel corresponds to a sunset detected based on an increase in solar radiance as estimated the first solar cell, and wherein the estimated warming of the fuel corresponds to a sunrise as estimated based on output of the second solar cell. ### Claim 13 A method for an engine, comprising: during a vehicle off condition, in response to detection of sunset via a first solar cell, pulsing a refueling valve (RV) coupling a fuel tank to a fuel vapor canister of an evaporative emissions control system to an open position; and in response to detection of sunrise via a second solar cell, pulsing the RV to a closed position. ### Claim 14 (depends on 13) The method of claim 13, wherein an output of the first solar cell and an output of the second solar cell are configured as inputs to a comparator circuit, the comparator circuit including one or more operational amplifiers, resistors, variable resistors, and logic gates. ### Claim 15 (depends on 14) The method of claim 14, wherein the resistors include each of a first variable resistor to delay opening the RV by a first duration after sunset, and a second variable resistor to delay closing the RV by a second duration after the sunrise. ### Claim 16 (depends on 15) The method of claim 15, further comprising, at initiation of the vehicle off condition, setting a first value of the first variable resistor and setting a second value of the second variable resistor based on a fuel level in the fuel tank. ### Claim 17 (depends on 16) The method of claim 16, wherein the comparator circuit is activated by a controller at the initiation of the vehicle off condition based on a higher than threshold fuel vapor load in the fuel vapor canister, the controller maintained inactive during operation of the comparator circuit during the vehicle off condition. ### Claim 18 A system for an engine in a vehicle, comprising: a controller with computer-readable instructions stored on non-transitory memory that when executed cause the controller to: in response to a request for a vehicle off, estimate a load in a fuel vapor canister of an evaporative emissions control system; and in response to a higher than threshold load in the fuel vapor canister, activate a comparator circuit to open a refueling valve (RV) regulating flow of fuel vapor between a fuel tank and the fuel vapor canister in response to a decrease in solar radiance as detected via a first solar cell configured on a surface of the vehicle. ### Claim 19 (depends on 18) The system of claim 18, wherein a time of opening the RV upon detection of the decrease in solar radiance is based on a fuel level in the fuel tank at vehicle off, and wherein upon opening of RV, air is drawn into the fuel tank via a vent line and the fuel vapor canister, the air desorbing fuel vapor from the canister and routing the desorbed fuel vapor to the fuel tank. ### Claim 20 (depends on 19) The system of claim 19, wherein the comparator circuit closes the RV upon an increase in solar radiance as detected via a second solar cell configures on the surface, a time of closing the RV upon detection of the increase in solar radiance based on the fuel level in the fuel tank; and wherein the opening and the closing of the RV occurs without waking up the controller.