Patent application number | Description | Published |
20130253799 | FUEL SYSTEM DIAGNOSTICS - Methods and systems are provided for detecting a fuel system leak. One or more of a boost pressure from a compressor and vacuum from an intake manifold is sequentially applied on a fuel tank. A leak is detected based on a subsequent change in fuel tank pressure. | 09-26-2013 |
20140019002 | SYSTEM AND METHOD FOR PERFORMING EVAPORATIVE LEAK DIAGNOSTICS IN A VEHICLE - A method is provided for performing an evaporative leak diagnostic for a vehicle. A valve in a diagnostic module is commanded to a vent position. The valve connects a fuel system to atmosphere. A pump in the diagnostic module is operated to measure a reference pressure across an orifice in the diagnostic module to provide a threshold. The valve is commanded to a test position. The pump is operated to place the fuel system in a low pressure state. A series of pressures in the fuel system is measured. A diagnostic code is provided after comparing the series of pressures to the threshold. | 01-16-2014 |
20140026865 | PASSIVE VENTURI PUMP FOR LEAK DIAGNOSTICS AND REFUELING - Systems and methods for operating a hybrid electric vehicle with a passive venturi pump are disclosed. In one example approach, a method comprises: during vehicle motion, passing air through a venturi coupled to the vehicle to generate vacuum; storing the generated in an accumulator; and, in response to a condition, discharging the stored vacuum to a vacuum consuming system of the vehicle. | 01-30-2014 |
20140069394 | FUEL SYSTEM DIAGNOSTICS - Methods and system are provided for identifying unintended closing (or corking) of a mechanical valve coupled to a fuel tank. If tank vent valve corking is identified during a leak test, fuel tank pressure data collected during the leak test is disregarded and not used to determine a fuel system leak. Instead, a fuel system leak test is repeated to improve reliability of test results. | 03-13-2014 |
20140074385 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for performing a vehicle-off fuel system leak test. A vehicle controller may be woken up after a vehicle has been in a key-off condition for a sufficient amount of time to monitor a fuel tank for pressure and temperature stabilization. If the pressure and temperature of the fuel tank is stable, a fuel pump may be operated to raise a fuel tank vapor pressure, and fuel system leaks are identified based on a rate of pressure decay from the fuel tank. | 03-13-2014 |
20140095049 | ENGINE COOLING SYSTEM MOTOR DRIVEN VACUUM PUMP - Embodiments for monitoring fuel system degradation are provided. In one example, a method comprises driving a cooling fan with an electric motor in a vehicle, and during selected conditions, also driving a vacuum pump with the electric motor through a clutch. In this way, fuel system degradation may be indicated without use of a separate motor to drive a pressure building device. | 04-03-2014 |
20140107906 | FUEL SYSTEM DEGRADATION TEST USING TWO FUEL TANKS - Embodiments for monitoring fuel system degradation are provided. In one example, a method for a vehicle comprises evacuating fuel from a first fuel tank to a second fuel tank, and indicating fuel system degradation in response to a change in fuel system pressure following the evacuation of fuel. In this way, fuel system degradation may be indicated without use of a separate pressure building device. | 04-17-2014 |
20140114550 | VEHICLE METHOD FOR BAROMETRIC PRESSURE IDENTIFICATION - A vehicle method for barometric pressure identification, including adjusting engine operation responsive to barometric pressure, the barometric pressure based on a pressure change at a sector of the fuel system when the sector is sealed with the vehicle travelling. The method may utilize a pressure change at the sealed sector of the fuel system, such as a sealed fuel tank, to identify barometric pressure, even with the engine off for extended durations of vehicle travel. As such, in a hybrid-vehicle application, including during hill descents in which the engine is maintained off, barometric pressure can still be updated. | 04-24-2014 |
20140130781 | FUEL SYSTEM DIAGNOSTICS - Methods and system are provided for distinguishing fuel tank vacuum generation due to canister purge valve degradation from vacuum generation due to canister vent valve degradation. A fuel tank vacuum level is monitored after sealing the fuel tank from the atmosphere following an engine pull-down. If there is an ensuing change in fuel tank vacuum, canister purge valve degradation is determined, else, canister vent valve degradation is determined. | 05-15-2014 |
20140209069 | CONTROLLING THE CLOSING FORCE OF A CANISTER PURGE VALVE PRIOR TO EXECUTING LEAK DIAGNOSTIC - A method for a vehicle having a fuel vapor canister coupled between a fuel tank and an engine intake manifold via an electronically controlled purge valve, comprises initiating a vapor leak test under predetermined conditions and in response to said initiation, fully opening said purge valve from a closed position to a fully open position for a predetermined time, and then fully closing said purge valve after said predetermined time and commencing said leak test. | 07-31-2014 |
20140216563 | CAPLESS REFUELING SYSTEM CLEANING USING ENGINE VACUUM - Methods and systems for cleaning a capless refueling system in a vehicle are disclosed. In one example approach, a method comprises, in response to a leak detected following a refueling event, cleaning the capless refueling system using engine vacuum. | 08-07-2014 |
20140230795 | FUEL SYSTEM CONTROL - Methods are provided for reliving excess vacuum from a fuel tank. In response to elevated fuel tank vacuum levels, a canister purge valve is opened to dissipate the vacuum to an engine intake manifold while the engine is not combusting. Alternatively, the purge valve is opened to dissipate the excess vacuum to the intake manifold while the engine is combusting during conditions when the likelihood of air-fuel ratio errors are lower or when any incurred errors are better tolerated. | 08-21-2014 |
20140251284 | MULTI-PATH PURGE EJECTOR SYSTEM - Systems and methods for a multi-path purging ejector are disclosed. In one example approach, a multi-path purge system for an engine comprises an ejector including a restriction, first and second inlets, and an outlet, and a shut-off valve hard-mounted to an intake of the engine and coupled to the outlet. | 09-11-2014 |
20140257668 | ENGINE-OFF REFUELING DETECTION METHOD - A method for an engine fuel system comprises, during an engine-off condition, indicating a refueling event based on a rate of change in fuel tank pressure, and aborting a diagnostic leak detection test based on the refueling event indication. Indicating a refueling event further comprises indicating a refueling event based on the rate of change in fuel tank pressure being greater than a first threshold when the canister vent valve is open, and greater than a second threshold when the canister vent valve is closed, the first threshold being less than the second threshold. | 09-11-2014 |
20140260549 | FUEL SYSTEM LEAK DETECTION USING PASSIVE VALVES - Methods and systems for fuel system leak detection using passive canister vent valves are disclosed. In one example approach, a method comprises generating engine off vacuum or pressure in a fuel system for leak diagnostics, where the pressure and vacuum are held via first and second mechanical relief valves positioned in parallel with one another and without a valve holding current. | 09-18-2014 |
20140260576 | METHOD AND SYSTEM TO VALIDATE A FUEL LEVEL INDICATOR IN A VEHICLE - A vehicle is provided with a controller and a fuel system having a fuel tank, a fuel level indicator (FLI), and a pressure sensor. The controller is configured to: pull a vacuum on the tank from an initial pressure to a reference pressure, and provide a diagnostic code in response to comparing a fuel level indicated by the FLI to a rate of pressure change in the tank. A method for performing a fuel level indicator (FLI) diagnostic for a vehicle is provided. A vacuum is pulled on the fuel tank from an initial pressure to a reference pressure. A diagnostic code is provided in response to comparing a fuel level indicated by an FLI to a rate of pressure change. | 09-18-2014 |
20140297071 | ESTIMATING VEHICLE FUEL REID VAPOR PRESSURE - Methods and systems are provided for estimating fuel volatility. During a vehicle-off condition following a refueling event, fuel volatility may be estimated. Based on estimated fuel volatility, fuel injection amount and leak test thresholds may be adjusted. | 10-02-2014 |
20140303830 | EVAPORATIVE EMISSION CONTROL SYSTEM - A combined system for detecting leaks in an evaporative emission control system and for inflating flat tires. The evaporative emission control system includes a vapor capture canister with a purge valve and a system pressure sensor, and the flat tire repair kit includes a reservoir containing tire inflation fluid, an attachment tube for attaching the reservoir to a tire, and a pump selectively connected to the evaporative emission control system and the reservoir. A controller is configured to perform the following actions: initiate a leak detection sequence by pressurizing the evaporative emission control system, and then performing a leak detection operation by measuring the pressure within the evaporative emission control system over time. A tire pressure monitoring system may be provided, allowing the pump to be switched between performing evaporative system testing and inflating a flat tire. | 10-09-2014 |
20140311461 | CANISTER PURGE VALVE SELF-CLEANING CYCLE - A method for a fuel system coupled to an engine comprising: under vacuum conditions, opening the fuel vapor canister purge valve, and generating pressure pulsations in a conduit coupled to the fuel vapor canister purge valve by opening and closing a fuel vapor canister vent valve one or more times while maintaining the fuel vapor canister purge valve open. In this way, contaminants and/or debris that may prevent the canister purge valve from closing completely may be dislodged and evacuated to the intake manifold. | 10-23-2014 |
20140316638 | HYBRID VEHICLE FUEL SYSTEM LEAK DETECTION - Methods and systems for fuel system leak detection in a hybrid electric vehicle using a fuel reservoir are disclosed. In one example approach, a method comprises, during an engine off condition, delivering fuel from a fuel tank into a reservoir while the fuel tank is vented to atmosphere, and sealing the fuel tank from atmosphere and indicating a leak based on pressure in the fuel tank. | 10-23-2014 |
20140318504 | AIR INTAKE SYSTEM HYDROCARBON TRAP PURGING - Methods and systems for purging a hydrocarbon trap in an engine intake in a vehicle are disclosed. In one example approach, a method comprises during an engine off condition, operating a pump in a purge line coupled to a fuel vapor canister in an emission control system to deliver fuel stored in a hydrocarbon trap in an intake of the engine to the fuel vapor canister. | 10-30-2014 |
20140318506 | AIR INTAKE SYSTEM HYDROCARBON TRAP PURGING - Methods and systems for passively purging a hydrocarbon trap in an engine intake in a vehicle are disclosed. In one example approach, a method comprises, in response to an ambient temperature decrease during an engine off condition while a fuel tank is sealed from atmosphere, delivering fuel stored in a hydrocarbon trap in an intake of the engine to a fuel vapor canister coupled to the fuel tank in an emission control system. | 10-30-2014 |
20140330482 | REFUELING DETECTION FOR DIAGNOSTIC MONITOR - Methods and systems for detecting a refueling event for diagnostics are disclosed. In one example approach a method comprises discontinuing leak diagnostics in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the leak diagnostics are being performed in the emission control system. | 11-06-2014 |
20140336873 | INTERNAL ORIFICE CHARACTERIZATION IN LEAK CHECK MODULE - Systems and methods for internal orifice characterization in an evaporative leak check module are disclosed. In one example approach, a method comprises operating a pump to draw air from an emission control system through an orifice to obtain a reference pressure, and indicating a leak in response to pressure in the emission control system remaining above a threshold pressure while operating the pump to decrease pressure in the emission control system, where the threshold pressure is based on a coded indication and the reference pressure. | 11-13-2014 |
20140345575 | CANISTER PURGING FOR PLUG-IN HYDRID ELECTRIC VEHICLES - A method for desorbing fuel vapors from a canister of a vehicle having an internal combustion engine and a fuel tank includes detecting the temperature within the interior of the fuel tank using a temperature sensor positioned within the fuel tank. The canister is in fluid communication with the fuel tank and an intake manifold of the engine of the vehicle. A vapor bypass valve is positioned along a flow line between the fuel tank and the canister. The vapor bypass valve is opened if the temperature inside the fuel tank falls below a pre-determined value. The low pressure region created within the fuel tank due to fall in temperature is utilized to route ambient air along with the fuel-vapors contained within the canister, towards the fuel tank, through the opened vapor bypass valve. | 11-27-2014 |
20140352796 | FUEL TANK DEPRESSURIZATION BEFORE REFUELING A PLUG-IN HYBRID VEHICLE - Methods and systems for controlling a locking mechanism on a fuel cap for refueling a vehicle are disclosed. In one example approach, a method comprises venting a fuel tank into a vapor absorbent canister in response to a request to refuel and unlocking the fuel cap in response to a predetermined temperature change in said canister. | 12-04-2014 |
20140360260 | FUEL LEVEL INFERENCE FROM CANISTER TEMPERATURES - Methods and systems for inferring a fuel level in a fuel tank based on temperature changes in a carbon canister are disclosed. In one example approach a method comprises, indicating a fuel level in a fuel tank based on a temperature change of adsorbent in a carbon canister during refueling. | 12-11-2014 |
20140374177 | FUEL SYSTEM CONTROL - Methods and systems are provided for accurately confirming fuel tank depressurization before unlocking a fuel door to enable refueling. Following a refueling request, a fuel system may be sealed from the atmosphere while one or more fuel system valves are adjusted to divert fuel tank pressure or vacuum to an engine intake. Depressurization may be inferred based on the presence of air or vapor flow into the intake as sensed by a manifold airflow sensor. | 12-25-2014 |
20150019066 | LEAK DETECTION FOR CANISTER PURGE VALVE - Methods and systems for detecting a leak in a canister purge valve are disclosed. In one example approach, a method comprises indicating a leak in response to a temperature change in a fuel vapor canister coupled to a fuel tank in an emission control system while the engine is in operation and a purge valve is closed. | 01-15-2015 |
20150020779 | FUEL TANK PRESSURE RELIEF VALVE CLEANING - Methods and systems for cleaning a pressure relieve valve for a fuel tank are disclosed. In one example approach a method for cleaning a pressure relief valve that is normally activated at a preset negative pressure in a fuel system comprises, during a test cycle, reducing fuel system pressure to a predetermined pressure which is higher than the preset pressure, and measuring pressure changes in the fuel system; and when not in the test cycle, periodically reducing the fuel system pressure to a third pressure which is less than said preset pressure. | 01-22-2015 |
20150025722 | LEAK DETECTION BASED ON FUEL LEVEL - Methods and systems for fuel system leak detection are disclosed. In one example approach, a method comprises, during an engine-on condition, delivering fuel from a fuel tank to one or more cylinders of the engine while the fuel tank is sealed off from atmosphere, and indicating a leak based on pressure in the fuel tank. For example, a leak may be indicated in response to a pressure decrease in the fuel tank greater than an expected pressure decrease, where the expected pressure decrease is based on a fuel level in the fuel tank. | 01-22-2015 |
20150025781 | CANISTER PURGE VALVE LEAK DETECTION SYSTEM - System for detecting leakage within a canister purge valve of an evaporative emission control system. The system includes a power train control module connected to the canister purge valve, configured to command the canister purge valve between open and closed positions. In addition, the system includes a flow meter having an inlet and an outlet. The inlet is in fluid communication with ambient air surrounding the vehicle, and the outlet is in fluid communication with an inlet of the canister purge valve. The system further includes a control module operatively connected to the flow meter. The control module is programmed to analyze flow through the flow meter; compare the measured flow to predetermined flow data; and to indicate whether that flow exceeds a predetermined level. | 01-22-2015 |
20150032357 | BAROMETRIC PRESSURE INFERENCE BASED ON TIRE PRESSURE - Methods and systems for detecting barometric pressure (BP) changes based on tire pressure changes are disclosed. In one example approach, a method comprises adjusting an evaporative leak detection threshold based on a change in barometric pressure, where the change in barometric pressure is based on a tire pressure change. | 01-29-2015 |
20150046026 | ENGINE-OFF LEAK DETECTION BASED ON PRESSURE - Methods and systems for fuel system leak detection are disclosed. In one example approach, a method comprises, in response to a pressure change in a fuel tank less than a threshold for a duration during engine-off conditions while the tank is sealed off from atmosphere, indicating a leak condition, and in response to a pressure change in the tank greater than the threshold during engine-off conditions while the tank is sealed off from atmosphere, indicating a no-leak condition. | 02-12-2015 |
20150075251 | DETECTING PRESSURE SENSOR OFFSET IN A PHEV FUEL TANK - A method for determining pressure sensor offset values in an evaporative emission control system. The method is performed during initial vehicle power up, and the method begins by receiving a reference signal indicating existing atmospheric pressure, as well as a check signal from a fuel tank pressure sensor indicating pressure within the fuel tank, at a time when the fuel system is open to atmosphere. A controller then calculates a sensor offset value based upon the reference signal and the check signal, and the controller stores the sensor offset value in a system memory location. During operation of the evaporative emission control system, the controller modifies pressure values received from the fuel tank pressure sensor by applying the sensor offset value. Whenever the system employs a reading from the fuel tank pressure sensor, that reading is corrected by applying the stored offset value. | 03-19-2015 |
20150075267 | FUEL TANK PRESSURE SENSOR RATIONALITY TEST FOR A PHEV - A method for verifying reliable operation of a fuel tank pressure transducer coupled to a fuel tank of a PHEV. The method monitors pressure and fuel level within the fuel tank, employing a fuel level sensor providing fuel level signals to a controller, as well as a pressure transducer providing pressure signals to the controller. The system identifies a sloshing event, as indicated by high amplitude, rapidly fluctuating fuel level signals, and it then analyzes the vapor dome pressure signals to determine whether vapor dome pressure signals respond to the sloshing event. Reliable operation of the fuel tank pressure transducer is indicated upon a determination that the vapor dome pressure signals appropriately respond to the sloshing event. | 03-19-2015 |
20150075501 | FUEL TANK PRESSURE SENSOR RATIONALITY TEST FOR A PHEV - A method for verifying the reliable operation of a fuel tank pressure transducer positioned within a fuel tank of a PHEV. The method detects the initiation of a refueling cycle, which leads to opening a system vent valve positioned between a carbon canister and a system vent, and opening a fuel tank isolation valve. A controller monitors fuel system pressure within the fuel tank and at the vent valve, and that device determines rates of change of the fuel system pressure within the fuel tank and at the outlet vent. Reliable operation of the fuel tank pressure transducer is indicated upon a determination that the rates of change of the fuel system pressure in the fuel tank and at the outlet vent are uniform within a predetermined range. | 03-19-2015 |
20150082866 | SERVO CONTROLLED EVAP LEAK DETECTION SYSTEM - A method and system for testing an evaporative emission control system for leaks. The method begins by setting a variable reference orifice to a preselected diameter. Then, a vacuum pump evacuates a reference volume in the vicinity of the variable reference orifice. The reference volume is defined by the vacuum pump, and the reference orifice. Then, after a specified evacuation time, the method determines a pressure in the reference volume. That pressure is stored as the threshold test value. The method continues by evacuating the entire EVAP system for a predetermined time. A leak can then be identified if after the evacuation, the system pressure falls at least to the threshold test value. Switching the vacuum pump between the first and second positions is accomplished with a changeover valve having parallel airways configured for evacuating a small volume to the reference orifice and also evacuating the entire EVAP system. | 03-26-2015 |
20150083087 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for identifying leaks on each of a fuel tank and a canister side of a fuel system using a single leak check module. A position of a switching valve coupled in the vapor line of the fuel system is adjusted to selectively couple the leak check module to either the fuel tank or the canister. Leak is detected based on a change in pressure at a reference orifice of the leak check module following applying of vacuum from a vacuum pump. | 03-26-2015 |
20150083088 | METHOD AND SYSTEM FOR DETECTING PHEV EVAP SYSTEM RECIRCULATION TUBE RELIABILITY - A method for detecting blockage within a recirculation tube of the evaporative emission control system of a PHEV measures the rise in interior temperature of a canister of the EVAP system, during the process of refueling, and notes an initial state of loading of the canister before refueling, indicative of the amount of hydrocarbons contained within the canister It is inferred that the recirculation tube is operative reliably if the rise in canister temperature is below a pre-determined temperature value. | 03-26-2015 |
20150085894 | METHOD FOR DIAGNOSING FAULT WITHIN A FUEL VAPOR SYSTEM - A method for diagnosing a fault within a evaporative emission control system of an automotive vehicle. The method monitors the carbon canister temperature during a system leak test. The leak test here is undertaken with the engine running, and engine vacuum is employed to evacuate the EVAP system. If the evacuation succeeds in reaching a target vacuum, and a temperature gain in the canister is observed, then the system infers proper system operation. Failure to achieve a target vacuum causes the system to determine a likely cause of the failure based on the temperature response of the carbon canister. | 03-26-2015 |
20150090006 | COMBINATION PRESSURE- AND VACUUM-BASED EVAP LEAK DETECTION METHOD - A method and system for conducting leak detection in an evaporative emission control system. The method performs a pressure-based leak test at selected intervals. The pressure-based test includes pressurizing the system, using a pump. Then, the system monitors pressure for a selected period. If system pressure falls below a threshold value during the selected period, the system identifies an initial leak. Upon identifying the initial leak, the system substitutes a vacuum-based leak test at each selected interval. The vacuum-based test includes evacuating the system, using the pump. The system then monitors system pressure for a selected period. If system pressure rises above a threshold value during the selected period, then the system identifies a subsequent leak. Upon receiving notification that the initial leak has been repaired, the system returns to pressure-based leak testing. Where a single pump is used, that pump is configured both for system pressurization and evacuation. | 04-02-2015 |
20150090008 | INFERENTIAL METHOD AND SYSTEM FOR EVAP SYSTEM LEAK DETECTION - A method for detecting leaks in an evaporative emission control system. The method begins by activating a PCM at a selected interval, for a selected period. During the selected period, the PCM monitors system pressure and temperature. The PCM then determines a relationship between changes in system temperature and changes in system pressure, and it identifies a leak based on predetermined criteria related to the relationship. The relationship can be the ideal gas law, which allows the calculation of an expected pressure, based upon differences in temperature. If the actual pressure is considerably below the expected pressure, then one can infer the presence of a leak. | 04-02-2015 |
20150090233 | HYBRID VEHICLE FUEL VAPOR CANISTER - Embodiments for controlling fuel vapors are provided. In one example, a method comprises initiating a purge of a fuel vapor canister responsive to a temperature profile at a vent side of the fuel vapor canister. In this way, release of fuel vapors to the atmosphere may be reduced. | 04-02-2015 |
20150090234 | PHEV EVAP SYSTEM CANISTER LOADING STATE DETERMINATION - An evaporative emission control system for a plug-in hybrid electric vehicle that indicates the level of loading of a carbon canister of the system. The system has multiple thermocouples positioned space apart from each other along a vapor flow path within the carbon canister. A controller is connected to each thermocouple, which monitors the temperature of the thermocouples. The controller indicates the level of saturation of the carbon canister based on certain pre-determined temperature criteria. | 04-02-2015 |
20150090235 | CPV-CONTROLLED EVAP LEAK DETECTION SYSTEM - A method and system for testing an evaporative emission control system for leaks. The method includes opening a canister purge valve by an amount sufficient to provide a flow equivalent to a predetermined orifice diameter. Then, a vacuum pump evacuates a reference volume consisting of the portion of the evaporative emission control system extending from the canister purge valve to an evacuation level control monitor. The system determines the pressure in the reference volume at the end of a specified evacuation time, and that value is stored as the threshold test value. Then, the system closes the canister purge valve and proceeds to evacuate the entire evaporative emission control system for a predetermined time. At the end of that time, the system identifies the absence of a leak if the system pressure falls at least to the threshold test value. A powertrain control module controls the canister purge valve. | 04-02-2015 |
20150105969 | SYSTEM AND METHODS FOR EVAPORATIVE EMISSIONS LEAK DETECTION BASED ON A VEHICLE LOCATION - A method for detecting evaporative emissions system leaks, comprising: adjusting a leak detection threshold based on a vehicle geographical location including jurisdiction borders; and indicating a leak based on the adjusted threshold. In this way, a vehicle may perform OBD EVAP leak tests in accordance with local regulations. This method allows for a single PCM to be installed in all vehicles of a certain model during manufacturing regardless of the jurisdiction where the vehicle will be sold, thereby reducing part complexity and simplifying the manufacturing process. | 04-16-2015 |
20150114089 | FUEL SYSTEM LEAK CHECK BASED ON FUEL REID VAPOR PRESSURE - A method for an evaporative emissions leak test, comprising: adjusting a pressure threshold based on a fuel volatility of a fuel contained in a fuel tank; and performing the evaporative emissions leak test based on the adjusted pressure threshold. By determining fuel volatility and adjusting a pressure threshold based on the fuel volatility, a more robust and accurate evaporative emissions leak test may be employed without adding additional components to a fuel system. | 04-30-2015 |
20150120108 | METHOD FOR PURGING OF AIR INTAKE SYSTEM HYDROCARBON TRAP - Methods and systems are provided for improving air intake system hydrocarbon trap purging during engine-off time in a hybrid electric vehicle. One method includes opening the throttle during vehicle motion under battery operation and allowing airflow through the trap to purge its contents into the fuel canister via the canister purge valve. Upon transition into the engine-on mode, fuel vapors are released from the canister into the engine intake. | 04-30-2015 |
20150120110 | FUEL SYSTEM CANISTER PURGE CONTROL - Methods and systems are provided for improving canister purging during the limited engine operation time in a hybrid electric vehicle. Prior to a transition into an engine-on mode, a canister heater is operated to heat the canister to an optimum temperature based on vehicle operating conditions. Upon transition into the engine-on mode, fuel vapors released from the heated canister are purged to an engine intake. | 04-30-2015 |
20150120133 | COOLING FAN ASSISTED ENGINE-OFF NATURAL VACUUM TEST - A method for a vehicle fuel system, comprising: during an engine-off condition, including an ambient temperature within a threshold range, operating a cooling fan to increase a fuel tank vacuum; and indicating leaks in the vehicle fuel system based on the increased vacuum. In this way, an EONV test may be run at mild ambient temperatures which would not otherwise result in the development of adequate fuel tank vacuum to pass the EONV test. | 04-30-2015 |
20150121999 | REFUELING DETECTION METHOD - Embodiments for detecting fuel events are presented. In an embodiment, a method comprises performing an action responsive to a fuel event indicated based on output from a hydrocarbon sensor positioned between a fuel tank and a fuel vapor canister. In this way, the hydrocarbon sensor may be used to detect fuel events and engine operation may be adjusted accordingly. | 05-07-2015 |
20150122229 | METHOD AND SYSTEM FOR ADJUSTING A FUEL TANK ISOLATION VALVE - Methods and systems are provided for adjusting and diagnosing a position of a fuel tank isolation valve (FTIV) of a fuel system. In one example, a method comprises adjusting a FTIV of a fuel system by sending an electrical pulse to the FTIV; and comparing a current draw of the FTIV to a known current draw profile to verify the position of the FTIV. In this way, the position of the FTIV may be diagnosed, thereby resulting in increased accuracy of subsequent valve control. | 05-07-2015 |
20150142293 | SYSTEM AND METHODS FOR DIAGNOSING PREMATURE REFUELING SHUTOFF - A method for localizing restrictions in a fuel system during refueling, comprising: monitoring fuel tank pressure, fuel vapor canister temperature, and evaporative leak check module pressure during a refueling event; and responsive to a premature shutoff event, indicating a location of a restriction among a plurality of locations based on whether monitored pressure and temperature changes during the refueling event are greater than respective thresholds. In this way, the cause of a premature shutoff event may be diagnosed without requiring additional sensors within the fuel system. | 05-21-2015 |
20150158377 | SYSTEMS AND METHODS FOR MANAGING BLEED EMISSIONS IN PLUG-IN HYBRID ELECTRIC VEHICLES - A method for a plug-in hybrid electric vehicle, comprising: during a first condition, including an engine-off condition and the plug-in hybrid electric vehicle coupled to an external power source, cooling a vapor canister based on an ambient temperature. In this way, bleed emissions may be reduced in PHEVs during conditions when the vehicle is parked and recharging at a high ambient temperature. | 06-11-2015 |
20150158378 | SYSTEMS AND METHODS FOR MANAGING BLEED EMISSIONS IN PLUG-IN HYBRID ELECTRIC VEHICLES - A method for a plug-in hybrid electric vehicle, comprising: during a first condition, including an engine-off condition and the plug-in hybrid electric vehicle coupled to an external power source; heating a fuel vapor canister based on a fuel tank vacuum; and opening a fuel tank isolation valve to draw heated vapors into a fuel tank. In this way, a passive purge operation may be executed, thereby purging the fuel vapor canister without forcing the engine to turn on. Thus, the vehicle may be operated at peak fuel economy without increasing emissions. | 06-11-2015 |
20150198103 | SYSTEMS AND METHODS FOR DETERMINING THE INTEGRITY OF A VEHICLE FUEL SYSTEM - A method, comprising: indicating a leak of a first diameter on a canister side of a fuel system following applying a vacuum to the fuel system with a fuel tank isolation valve closed; and indicating a leak of a second diameter on a fuel tank side of the fuel system, based on a vacuum decay in an isolated fuel tank following applying a vacuum to the fuel system with the fuel tank isolation valve open. In this way, an evaporative leak check module with a single reference orifice may be used to determine leaks of multiple sizes in multiple sectors of a fuel system. This may allow current production models to meet more stringent emissions regulations in the future. | 07-16-2015 |
20150198123 | SYSTEMS AND METHODS FOR DETERMINING THE INTEGRITY OF A VEHICLE FUEL SYSTEM - A method, comprising: indicating leakage on a canister side of a fuel system based on a first fuel system pressure following applying a vacuum to the fuel system with a fuel tank isolation valve closed; and indicating leakage on a fuel tank side of the fuel system based on the first fuel system pressure and a second fuel system pressure following applying a vacuum to the fuel system with the fuel tank isolation valve open. In this way, an ELCM with a single reference orifice may be used to perform a leak test with two different thresholds for leak detection. This may allow vehicles currently in production to meet future emissions standards without costly upgrades to the ELCM. | 07-16-2015 |
20150211914 | SYSTEM AND METHODS FOR ULLAGE SPACE FUEL LEVEL ESTIMATION - A method for a vehicle, comprising: indicating a true fill level of a fuel tank based on a fuel vapor canister temperature profile during a refueling event. In this way, a quantity fuel dispensed over the maximum fill level of the fuel tank may be accounted for, regardless of the fuel level sensor reading. | 07-30-2015 |
20150211952 | CLEANING CYCLE FOR CAPLESS REFUELING NECK - A method for a vehicle, comprising: following a refueling event, venting a capless refueling assembly to a fuel tank; and then executing an evaporative emissions leak test. In this way, residual fuel trapped in the capless refueling assembly may be removed. This, in turn will prevent a pressure build-up in the capless refueling assembly which could lead to the downstream door opening during a leak test, thereby confounding results. | 07-30-2015 |
20150219522 | CORRELATION BASED FUEL TANK LEAK DETECTION - A method for an engine, comprising: sealing a fuel tank; and indicating fuel system degradation based on a comparison of a first correlation coefficient, determined based on a change in fuel tank pressure and a change in fuel tank temperature, to a second correlation coefficient determined based on a change in ambient pressure and a change in ambient temperature. In this way, leak tests, such as engine-off natural vacuum tests, may be performed without knowledge of the properties of the fuel stored in the fuel tank. | 08-06-2015 |
20150226138 | FUEL TANK DEPRESSURIZATION BEFORE REFUELING A PLUG-IN HYBRID VEHICLE - A method for operating a vehicle system is provided. The method includes monitoring a change in a temperature of the fuel vapor canister coupled to a fuel tank via a canister temperature sensor and adjusting operation of a fuel tank isolation valve based on the change in temperature of the fuel vapor canister. | 08-13-2015 |
20150240756 | METHODS AND SYSTEMS FOR PURGING VEHICLE FUEL VAPORS - Systems and methods for improving fuel vapor purging for a vehicle are presented. In one example, a fuel vapor storage canister vent valve is housed in a fuel vapor storage canister for the purposes of heating contents of the fuel vapor storage canister and venting the fuel vapor storage canister to atmosphere. | 08-27-2015 |
20150243109 | METHOD FOR TRIGGERING A VEHICLE SYSTEM MONITOR - Methods and systems are provided for improving the frequency of attempting and successfully completing one or more on-board diagnostic routines. Engine operating conditions are predicted based on a vehicle operator's driving pattern and routines are initiated if the predicted conditions match the conditions required for performing the routine. If the conditions do not match, entry and/or execution conditions of the routine are adjusted to better match the predicted conditions, so as to enable the routine to be attempted. | 08-27-2015 |