# US 9,751,396 B2 · Fuel tank pressure sensor rationality for a hybrid vehicle during refueling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,396 B2 - Document ID: US9751396B2 - Status: Granted - Kind: B2 - Application number: 14/630,314 - Filed: 2015-02-24 - Published: 2016-08-25 - Granted: 2017-09-05 - Earliest claimed: 2015-02-24 - Assignees: Ford Global Technologies, LLC - Applicants: Ford Global Technologies, LLC - Inventors: Aed M. Dudar - Web page: https://patentgrep.com/patent/US9751396B2 ## CPC - B60K 15/03504: {adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems} - B60K 15/03519: {Valve arrangements in the vent line} - B60W 20/16: for reducing engine exhaust emissions - F02D 29/02: peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers - F02D 41/003: {Adding fuel vapours, e.g. drawn from engine fuel reservoir} - F02D 41/222: {relating to the failure of sensors or parameter detection devices} - F02M 25/0809: {Judging failure of purge control system} - F02M 25/089: {Layout of the fuel vapour installation} - B60K 2015/0321: {characterised by special sensors, the mounting thereof} - B60K 2015/03302: {Electromagnetic valves} - B60K 2015/03514: {with vapor recovery means} - B60K 2015/03576: {Venting during filling the reservoir} - B60W 2530/00: Input parameters relating to vehicle conditions or values, not covered by groups B60W2510/00 or B60W2520/00 - B60W 2710/06: Combustion engines, Gas turbines - F02D 2041/223: {Diagnosis of fuel pressure sensors} - F02D 2200/0602: Fuel pressure - Y10S 903/905: Combustion engine - 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 - 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) - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS ## Abstract Methods and systems are provided for performing fuel tank pressure sensor rationality for a hybrid electric vehicle during refueling. In one example, a method may include indicating degradation of the fuel tank pressure sensor based on the pressure detected in the canister vent line when the canister vent line is restricted. ## Claims ### Claim 1 A method for a fuel emissions system of a hybrid vehicle, comprising: during a refueling event when a fuel tank is being refueled and while a fuel tank level is increasing, maintaining a fuel vapor canister vent line restriction; and indicating degradation of a fuel tank pressure sensor based on a pressure in a canister vent line. ### Claim 2 (depends on 1) The method for a fuel emissions system of a hybrid vehicle of claim 1, further comprising adjusting one or more engine operating parameters based on the indicated degradation. ### Claim 3 (depends on 1) The method for a fuel emissions system of a hybrid vehicle of claim 1, wherein maintaining the fuel vapor canister vent line restriction during refueling further comprises placing a change-over valve positioned in the canister vent line in a first position. ### Claim 4 (depends on 3) The method for a fuel emissions system of a hybrid vehicle of claim 3, wherein when the change-over valve is in the first position, the canister vent line is coupled to atmosphere via a first flow path and a second flow path, the second flow path introducing the restriction via a deactivated vacuum pump. ### Claim 5 (depends on 1) The method for a fuel emissions system of a hybrid vehicle of claim 1, wherein indicating degradation of a fuel tank pressure sensor based on a pressure in the canister vent line comprises correlating the pressure in the canister vent line to fuel tank pressure sensor output, the pressure in the canister vent line determined by a canister vent line pressure sensor. ### Claim 6 (depends on 5) The method for a fuel emissions system of a hybrid vehicle of claim 5, wherein correlating pressure in the canister vent line and the fuel tank pressure sensor output comprises: comparing the fuel tank pressure sensor output with canister vent line pressure sensor output; and indicating fuel tank isolation valve degradation when the canister vent line pressure sensor output changes by less than a threshold amount during the refueling event, even as the fuel tank pressure sensor output changes. ### Claim 7 (depends on 5) The method for a fuel emissions system of a hybrid vehicle of claim 5, wherein correlating the canister vent line pressure and the fuel tank pressure sensor signal further comprises: comparing a rate of change of fuel tank pressure sensor output with a rate of change of canister vent line pressure sensor output; and indicating fuel tank pressure sensor degradation when the rate of change of fuel tank pressure sensor output is lower than the rate of change of the canister vent line pressure sensor output by at least a threshold amount. ### Claim 8 (depends on 5) The method for a fuel emissions system of a hybrid vehicle of claim 5, wherein correlating the canister vent line pressure and the fuel tank pressure sensor signal further comprises: comparing a rate of change of fuel tank pressure sensor output with a rate of change of canister vent line pressure sensor output; and indicating canister vent line pressure sensor degradation when the rate of change of the canister vent line pressure sensor is lower than the rate of change of the fuel tank pressure sensor output by at least a threshold amount. ### Claim 9 A system for a hybrid-electric vehicle, comprising: a fuel tank isolation valve coupled in a conduit between a fuel tank and a fuel vapor canister; a fuel tank pressure sensor; an evaporative leak check module (ELCM) coupled in a conduit between the fuel vapor canister and atmosphere, the ELCM comprising a vacuum pump, an ELCM pressure sensor, and a change-over valve operable between a first position and a second position; and a controller configured with instructions stored in non-transitory memory that when executed cause the controller to: during refueling of the fuel tank, perform an evaporative leak check routine by: adjusting the change-over valve to the first position; and comparing fuel tank pressure sensor output and ELCM pressure sensor output and indicating degradation of the fuel tank pressure sensor when a rate of change of the fuel tank pressure sensor output is lower than a rate of change of the ELCM pressure sensor output by at least a threshold amount. ### Claim 10 (depends on 9) The system of claim 9, wherein the change-over valve is configured to couple the fuel vapor canister to atmosphere via a first, unrestricted flow path and a second, restricted flow path when in the first position. ### Claim 11 (depends on 10) The system of claim 10, where the change-over valve is further configured to couple the fuel vapor canister to atmosphere via the vacuum pump when in the second position. ### Claim 12 (depends on 11) The system of claim 11, wherein the change-over valve comprises a solenoid that places the change-over valve into the first position when de-energized and into the second position when energized. ### Claim 13 (depends on 9) The system of claim 9, wherein the evaporative leak check routine is performed only when fuel tank pressure is within a threshold range of atmospheric pressure. ### Claim 14 (depends on 9) The system of claim 9, wherein during the evaporative leak check routine, the fuel tank isolation valve is open. ### Claim 15 (depends on 9) The system of claim 9, wherein the evaporative leak check routine is further performed by monitoring the ELCM pressure sensor output during the refueling and indicating degradation of the fuel tank isolation valve when the ELCM pressure sensor output changes by less than a threshold amount. ### Claim 16 (depends on 9) The system of claim 9, wherein the evaporative leak check routine is further performed by comparing fuel tank pressure sensor output and ELCM pressure sensor output and indicating degradation of the ELCM pressure sensor when the rate of change of the ELCM pressure sensor output is lower than the rate of change of the fuel tank pressure sensor output by at least a threshold amount. ### Claim 17 A method, comprising: responsive to a request to perform a fuel tank refuel, comparing fuel tank pressure to atmospheric pressure; when fuel tank pressure is not equal to atmospheric pressure, indicating degradation of a fuel tank pressure sensor based on a correlation between fuel tank pressure sensor output and canister vent line pressure during fuel tank depressurization prior to the fuel tank refuel; and when fuel tank pressure is substantially equal to atmospheric pressure, indicating degradation of the fuel tank pressure sensor based on a correlation between fuel tank pressure sensor output and canister vent line pressure during the fuel tank refuel and while a fuel tank level is increasing. ### Claim 18 (depends on 17) The method of claim 17, wherein when fuel tank pressure is not equal to atmospheric pressure, indicating degradation of the fuel tank pressure sensor comprises: placing a change-over valve positioned in a canister vent line into a second position; opening a fuel tank isolation valve coupled in a conduit between the fuel tank and a fuel vapor canister; and indicating degradation of the fuel tank pressure sensor when a rate of change of fuel tank pressure sensor output is less than a rate of change of canister vent line pressure during the fuel tank depressurization. ### Claim 19 (depends on 17) The method of claim 17, wherein when fuel tank pressure is equal to atmospheric pressure, indicating degradation of the fuel tank pressure sensor comprises: placing a change-over valve positioned in a canister vent line into a first position; opening a fuel tank isolation valve coupled in a conduit between the fuel tank and a fuel vapor canister; and indicating degradation of the fuel tank pressure sensor when a rate of change of fuel tank pressure sensor output is less than a rate of change of canister vent line pressure during the fuel tank refuel. ### Claim 20 (depends on 19) The method of claim 19, wherein placing the change-over valve into the first position creates a restriction in a flow path between the canister vent line and atmosphere, and wherein canister vent line pressure is determined via a pressure sensor positioned in the flow path.