Patent application number | Description | Published |
20100224171 | FUEL VAPOR PURGING DIAGNOSTICS - Systems and methods are provided for monitoring reverse flow of fuel vapors and/or air through a vehicle fuel vapor recovery system, said fuel vapor recovery system coupled to an engine intake of a boosted internal combustion engine. One example method comprises, during boost, when the fuel vapor recovery system is commanded to be sealed from the intake, indicating degradation based on a pressure value in the fuel vapor recovery system. | 09-09-2010 |
20110023837 | FUEL VAPOR PURGING DIAGNOSTICS - Systems and methods are provided for monitoring reverse flow of fuel vapors and/or air through a vehicle fuel vapor recovery system, said fuel vapor recovery system coupled to an engine intake of a boosted internal combustion engine. One example method comprises, during boost, when the fuel vapor recovery system is commanded to be sealed from the intake, indicating degradation based on a pressure value at a venturi in the fuel vapor recovery system. | 02-03-2011 |
20110079201 | DIAGNOSTIC STRATEGY FOR A FUEL VAPOR CONTROL SYSTEM - A method for operating a fuel vapor control system included in a vehicle having an internal combustion engine is provided. The method may include storing positive pressure or negative pressure in an isolated fuel tank, transferring at least a portion of the positive pressure or the negative pressure to an evaporation canister region, and determining degradation of the evaporation canister based on a pressure response of the evaporation canister region while the evaporation canister region is isolated from the fuel tank. In this way, it is possible to utilize pressure that may be passively generated in one portion of the system, even during shut-down engine operation, to verify the integrity of another portion of the system. | 04-07-2011 |
20110139120 | METHOD AND SYSTEM FOR PRE-IGNITION CONTROL - Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition. | 06-16-2011 |
20110144893 | METHOD AND SYSTEM FOR PRE-IGNITION CONTROL - Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition. | 06-16-2011 |
20110168140 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - A method and system for fuel vapor control in a hybrid vehicle (HEV). The HEV fuel vapor recovery system includes a fuel tank isolation valve, which is normally closed to isolate storage of refueling from storage of diurnal vapors. The method for fuel vapor control includes selectively actuating the fuel tank isolation valve during interrelated routines for refueling, fuel vapor purging, and emission system leak detection diagnostics to improve regulation of pressure and vacuum the HEV fuel vapor recovery system. | 07-14-2011 |
20120055452 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - A method and system for fuel vapor control in a hybrid vehicle (HEV). The HEV fuel vapor recovery system includes a fuel tank isolation valve, which is normally closed to isolate storage of refueling from storage of diurnal vapors. The method for fuel vapor control includes selectively actuating the fuel tank isolation valve during interrelated routines for refueling, fuel vapor purging, and emission system leak detection diagnostics to improve regulation of pressure and vacuum the HEV fuel vapor recovery system. | 03-08-2012 |
20120073542 | METHOD AND SYSTEM FOR PRE-IGNITION CONTROL - Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition. | 03-29-2012 |
20120138017 | FUEL IDENTIFICATION BASED ON CRANKSHAFT ACCELERATION - Systems and methods for identifying alcohol content of a fuel in an engine. In one example approach, a method comprises adjusting fuel injection to the engine based on fuel alcohol content identified from crankshaft acceleration. For example, the crankshaft acceleration may be generated by modulating an air/fuel ratio in a selected cylinder across a range of air/fuel ratios while keeping the engine at stoichiometry. | 06-07-2012 |
20120211087 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for monitoring a fuel vapor recovery system including a fuel tank isolation valve coupled between a fuel tank and a canister. During selected conditions, the valve is modulated and pressure pulsations in the fuel vapor recovery system are monitored. Valve degradation is identified based on correlations between the valve modulation and the resultant pressure pulsations. | 08-23-2012 |
20120215399 | SYSTEM AND METHOD FOR PERFORMING EVAPORATIVE LEAK DIAGNOSTICS IN A VEHICLE - A vehicle is provided with a fuel system, a controller, and a diagnostic module with an orifice, a pressure sensor, and a pump, the module connecting the fuel system to atmosphere. The controller measures a reference pressure across the orifice to provide a threshold, isolates the fuel system, and provides a code in response to comparing a series or measured pressures to the threshold. A method for performing an evaporative leak diagnostic is provided. A valve in a diagnostic module is commanded to a vent position. A pump is operated to measure a reference pressure across an orifice to provide a threshold. A valve is commanded to a test position. The pump is operated to place the fuel system in a low pressure state, and a series of pressures in the fuel system is measured. A diagnostic code is provided after comparing the series of pressures to the threshold. | 08-23-2012 |
20120227580 | Fuel System Diagnostics - An emissions control system is provided that comprises a fuel tank, a hydrocarbon filter element, and a three-way valve coupled between the hydrocarbon filter element and the atmosphere. The three-way valve is comprised of three ports, a purge port, a reference port, and a sealed port, and enables identification of degradation of the emissions control system. The arrangement of the ports on the valve enables a simplified testing method that reduces background errors caused by transitioning between various operating positions. | 09-13-2012 |
20120227714 | Method and System for Humidity Sensor Diagnostics - Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional. | 09-13-2012 |
20120227719 | Method and System for Humidity Sensor Diagnostics - Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional. | 09-13-2012 |
20120265396 | Distinguishing Between EGR Valve and Oxygen Sensor Degradation - A diagnostic method for an engine having a valve for controlling dilution of intake air. The method comprises, during engine fueling, indicating a degradation of the valve when the valve is commanded closed but sensor output corresponds to an oxygen level below that of air. The method further comprises, absent engine fueling, indicating degradation of the sensor when the valve is commanded closed but the sensor output corresponds to an oxygen level below that of air. | 10-18-2012 |
20120330536 | METHOD AND SYSTEM FOR PRE-IGNITION CONTROL - Methods and systems are provided for mitigating engine pre-ignition based on a feed-forward likelihood of pre-ignition and feedback from a pre-ignition event. In response to an indication of pre-ignition, a cylinder may be enriched while an engine load is limited. The enrichment may be followed by an enleanment to restore exhaust catalyst feed-gas oxygen levels. The mitigating steps may be adjusted based on engine operating conditions, a pre-ignition count, as well as the nature of the pre-ignition. | 12-27-2012 |
20130032127 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for operating an engine to generate vacuum for a subsequent leak detection routine. During a selected key-off condition, a starter motor is operated to spin the engine unfueled and generate intake vacuum for the leak detection. Fuel vapors drawn during the spinning are stored in an auxiliary canister that is purged along with a main canister during purging conditions. | 02-07-2013 |
20130112176 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for generating sufficient vacuum to enable a leak detection routine. While a fuel tank pressure is within mechanical limits, fuel vapors are purged from a canister to an engine with an isolation valve open to generate a desired level of vacuum in the fuel tank. Thereafter, the fuel tank is isolated and leak detection is performed concurrent to the purging. | 05-09-2013 |
20130184969 | AIR/FUEL IMBALANCE MONITOR - Systems and methods for monitoring cylinder air/fuel imbalances are provided. In one example approach, a method comprises, identifying a cylinder with a potential air/fuel imbalance based on crankshaft accelerations generated by a series of rich, lean, and stoichiometric conditions in the cylinder while keeping the engine at stoichiometry. | 07-18-2013 |
20130213355 | FUEL IDENTIFICATION BASED ON CRANKSHAFT ACCELERATION - Systems and methods for identifying alcohol content of a fuel in an engine. In one example approach, a method comprises adjusting fuel injection to the engine based on fuel alcohol content identified from crankshaft acceleration. For example, the crankshaft acceleration may be generated by modulating an air/fuel ratio in a selected cylinder across a range of air/fuel ratios while keeping the engine at stoichiometry. | 08-22-2013 |
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 |
20130255599 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for expediting engine system heating by stagnating coolant in one of a plurality of loops in an engine cooling system. Degradation of the various valves and thermostats of the cooling system can be diagnosed by adjusting the valve and monitoring changes in one or more of coolant temperature, transmission temperature and cabin temperature. Based on engine operating conditions, the various valves may be adjusted to vary coolant temperature in different regions of the cooling system, thereby providing fuel economy benefits. | 10-03-2013 |
20130255603 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for expediting engine system heating by stagnating coolant in one of a plurality of loops in an engine cooling system. Degradation of the various valves and thermostats of the cooling system can be diagnosed by adjusting the valve and monitoring changes in one or more of coolant temperature, transmission temperature and cabin temperature. Based on engine operating conditions, the various valves may be adjusted to vary coolant temperature in different regions of the cooling system, thereby providing fuel economy benefits. | 10-03-2013 |
20130255604 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for diagnosing each of a plurality of engine cooling system components including various valves and grill shutters. Each valve may be individually closed and opened for a specified duration, and corresponding changes in coolant temperature may be monitored. If all the components are functional, the various valves may be adjusted to stagnate coolant at the engine and expedite engine warm-up during a cold-start. | 10-03-2013 |
20130255605 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for diagnosing each of a plurality of engine cooling system components including various valves and grill shutters. Each valve may be individually closed and opened for a specified duration, and corresponding changes in coolant temperature may be monitored. If all the components are functional, the various valves may be adjusted to stagnate coolant at the engine and expedite engine warm-up during a cold-start. | 10-03-2013 |
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 |
20140033802 | FUEL SYSTEM DIAGNOSTICS - An emissions control system is provided that comprises a fuel tank, a hydrocarbon filter element, and a three-way valve coupled between the hydrocarbon filter element and the atmosphere. The three-way valve is comprised of three ports, a purge port, a reference port, and a sealed port, and enables identification of degradation of the emissions control system. The arrangement of the ports on the valve enables a simplified testing method that reduces background errors caused by transitioning between various operating positions. | 02-06-2014 |
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 |
20140076249 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 03-20-2014 |
20140081549 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 03-20-2014 |
20140081550 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 03-20-2014 |
20140081551 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 03-20-2014 |
20140081564 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 03-20-2014 |
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 |
20140142819 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for expediting engine system heating by stagnating coolant in one of a plurality of loops in an engine cooling system. Degradation of the various valves and thermostats of the cooling system can be diagnosed by adjusting the valve and monitoring changes in one or more of coolant temperature, transmission temperature and cabin temperature. Based on engine operating conditions, the various valves may be adjusted to vary coolant temperature in different regions of the cooling system, thereby providing fuel economy benefits. | 05-22-2014 |
20140144218 | ENGINE COOLING SYSTEM CONTROL - Methods and systems are provided for diagnosing each of a plurality of engine cooling system components including various valves and grill shutters. Each valve may be individually closed and opened for a specified duration, and corresponding changes in coolant temperature may be monitored. If all the components are functional, the various valves may be adjusted to stagnate coolant at the engine and expedite engine warm-up during a cold-start. | 05-29-2014 |
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 |
20140244135 | DISTINGUISHING BETWEEN EGR VALVE AND OXYGEN SENSOR DEGRADATION - A diagnostic method for an engine having a valve for controlling dilution of intake air. The method comprises, during engine fueling, indicating a degradation of the valve when the valve is commanded closed but sensor output corresponds to an oxygen level below that of air. The method further comprises, absent engine fueling, indicating degradation of the sensor when the valve is commanded closed but the sensor output corresponds to an oxygen level below that of air. | 08-28-2014 |
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 |
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 |
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 |
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 |
20150047339 | METHOD FOR ESTIMATING CHARGE AIR COOLER CONDENSATION STORAGE AND/OR RELEASE WITH TWO INTAKE OXYGEN SENSORS - Methods and systems are provided for estimating water storage in a charge air cooler (CAC). In one example, engine operation may be adjusted responsive to water storage parameters at the CAC, the water storage parameters based on an output of a first oxygen sensor positioned downstream of the CAC and a second oxygen sensor positioned upstream of the CAC. Further, operation of the first oxygen sensor and the second oxygen sensor may be diagnosed during certain engine operation conditions wherein no condensate is forming in the CAC. | 02-19-2015 |
20150066334 | METHOD AND SYSTEM FOR HUMIDITY SENSOR DIAGNOSTICS - Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional. | 03-05-2015 |
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 |
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 |
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 |
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 |
20150147949 | METHOD FOR ADJUSTING VEHICLE GRILLE SHUTTERS BASED ON VEHICLE SPEED AND DIRECTION OF GRILLE SHUTTER ADJUSTMENT - Methods and systems are provided for adjusting vehicle grille shutters based on a direction of motion of the grille shutters. In one example, a method includes adjusting a motor coupled to the grille shutters based on the direction of motion of the grille shutters, a desired opening of the grille shutters, and vehicle speed. Further, the method may include determining the direction of motion of the grille shutters based on a desired motor position relative to an actual motor position. | 05-28-2015 |
20150149043 | METHOD AND SYSTEM FOR ADJUSTING GRILLE SHUTTERS BASED ON TEMPERATURE AND POSITION FEEDBACK - Methods and systems are provided for adjusting vehicle grille shutters based on engine coolant temperature. In one example, a method includes adjusting grille shutters based on engine coolant temperature and additional engine operating conditions when engine coolant temperature is below a threshold and adjusting the grille shutters base on the engine coolant temperature only when the engine coolant temperature is above the threshold. Further, the method may include recalibrating a position of the grille shutters based on a grille shutter position error. | 05-28-2015 |
20150152801 | METHOD FOR INFERRING BAROMETRIC PRESSURE AT LOW THROTTLE ANGLES - Methods and systems are provided for estimating barometric pressure based on a reference barometric pressure and manifold pressures at two different altitudes. In one example, a method may include adjusting an operating condition of the engine based on barometric pressure during engine operation at throttle angles less than a threshold, the barometric pressure based on a current manifold pressure relative to a reference manifold pressure at a current throttle angle and reference barometric pressure. Further, the method may include adjusting a manifold pressure sensor output based on an offset of the manifold pressure sensor. | 06-04-2015 |
20150152802 | METHOD FOR DETERMINING AN OFFSET OF A MANIFOLD PRESSURE SENSOR - Methods and systems are provided for determining an offset of a manifold pressure sensor. In one example, an engine method may include indicating degradation of the manifold pressure sensor based on a sensor offset, the sensor offset based on a manifold pressure measured at a first throttle angle, a barometric pressure at a second throttle angle, a reference manifold pressure at the first throttle angle and reference barometric pressure, and the reference barometric pressure. Further, the method may include adjusting an output of the manifold pressure sensor by the determined sensor offset. | 06-04-2015 |
20150184620 | METHOD AND SYSTEM FOR FUEL VAPOR CONTROL - Methods and systems are provided for monitoring a fuel vapor recovery system including a fuel tank isolation valve coupled between a fuel tank and a canister. During selected conditions, the valve is modulated and pressure pulsations in the fuel vapor recovery system are monitored. Valve degradation is identified based on correlations between the valve modulation and the resultant pressure pulsations. | 07-02-2015 |
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 |
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 |
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 |
20150279194 | VEHICLE LIGHT ANOMALY STATE WARNING - A vehicle system includes a communication interface in communication with a processing device. The communication interface is configured to receive ambient light information from a remote server over a communication network. The processing device is configured to selectively enable a vehicle lighting system in accordance with the ambient light information. | 10-01-2015 |
20150285111 | CRANKCASE INTEGRITY BREACH DETECTION - Methods and systems are provided for using a crankcase vent tube pressure or flow sensor for diagnosing a location and nature of crankcase system integrity breach. The same sensor can also be used for diagnosing air filter plugging and PCV valve degradation. Use of an existing sensor to diagnose multiple engine components provides cost reduction and sensor compaction benefits. | 10-08-2015 |
20150354480 | SYSTEM AND METHODS FOR ENGINE-OFF NATURAL VACUUM TESTS - A method for a vehicle, comprising: during a first condition, closing a canister vent valve responsive to an engine-off event without initiating an engine-off natural vacuum test; during a second condition, following the first condition, closing the canister vent valve responsive to a vehicle-off event; and then initiating an engine-off natural vacuum test. In this way, the completion percentage of the engine-off natural vacuum test will increase. | 12-10-2015 |
20150354489 | METHOD AND SYSTEM FOR HUMIDITY SENSOR DIAGNOSTICS - Methods and systems are provided for an engine including a humidity sensor. Degradation of the humidity sensor may be determined based on a change in intake air relative humidity as compared to a change in intake air temperature or pressure, under selected conditions. An amount of exhaust gas recirculated to an engine intake is adjusted differently based on whether the humidity sensor is degraded or functional. | 12-10-2015 |
20160025589 | EVAPORATIVE EMISSIONS TESTING BASED ON HISTORICAL AND FORECAST WEATHER DATA - A method for a vehicle, comprising: initiating an engine-off natural vacuum test based on an ambient temperature change potential over a testing duration. The ambient temperature change potential may be based on historic weather data and further based on forecast weather data. In this way, the engine-off natural vacuum test may be executed only when conditions favor an in-tank temperature change significant enough to cause a threshold change in fuel tank pressure, thus reducing the number of aborted tests and increasing the test's overall performance metrics. | 01-28-2016 |