Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Methods and systems are provided for controlling a fuel system in a hybrid vehicle. Before canister purging is stopped by closing a purge valve, a canister vent valve is closed to hold fuel tank vacuum. Then, during a subsequent canister purge, the purge valve is opened before opening the vent valve, allowing canister purge to initiate under fuel tank vacuum conditions.

Abstract: A method for operating a fuel system is disclosed. The method includes sequentially purging fuel vapors from each of a plurality of regions of a canister. Purging a region includes opening an air inlet valve associated with that region and maintaining air inlet valves associated with each other region closed to direct fuel vapors to at least one purge outlet.

Abstract: A method for improving purging of fuel vapors from a fuel vapor storage canister to an engine is presented. In one example, the method adjusts engine operation to provide sonic flow between a canister and the engine. In this way, it may be possible to lower an amount of fuel vapors stored in a canister while the engine continues to operate efficiently.

Abstract: 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.

Abstract: 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.

Abstract: A method for reducing particulate matter emitted by an engine is disclosed. In one example, the start of fuel injection timing is adjusted in response to a change in engine operating conditions. In particular, start of injection timing may be advanced and then retarded to promote fuel vaporization.

Abstract: 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.

Abstract: A method for testing a vapor purge system (VPS) for an internal combustion engine, and a hybrid vehicle having the VPS include a controller for closing a first valve coupled between a carbon canister of the VPS and the ambient environment, motoring the engine to pull a vacuum on the VPS, closing a second valve coupled between the carbon canister and the engine, and monitoring pressure in the VPS. The VPS has a carbon canister coupled to the engine via a first valve and coupled to atmosphere via a second valve, and a pressure transducer.

Abstract: 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.

Abstract: A method for testing a vapor purge system (VPS), and the vehicle having the VPS, including a controller for measuring a VPS pressure, closing a first valve coupling a VPS carbon canister and the environment, decreasing VPS pressure if it is greater than a threshold, and monitoring VPS pressure for a time period when the engine is at rest and the vehicle is operating. The pressure is decreased by opening a second valve coupling the fuel tank and the engine while the engine is running, and closing the second valve when the pressure is below the threshold. Another method for testing a VPS includes closing a first valve, closing a second valve, measuring the VPS pressure to provide a reference pressure with an associated profile, and monitoring VPS pressure compared to the profile for a time period.

Abstract: 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.

Abstract: A hydrocarbon canister purge system includes a hydrocarbon storage canister, a fuel tank disposed in fluid communication with the hydrocarbon storage canister, an engine disposed in fluid communication with the hydrocarbon storage canister, a hydrocarbon sensor provided in the hydrocarbon storage canister and a controller disposed in signal-receiving communication with the hydrocarbon sensor and in signal-transmitting communication with the engine.

Abstract: A method for reducing particulate matter emitted by an engine is disclosed. In one example, the start of fuel injection timing is adjusted in response to a change in engine operating conditions. In particular, start of injection timing may be advanced and then retarded to promote fuel vaporization.

Abstract: A method and apparatus for constructing spatial representations of referents is provided. The method and apparatus have application in any area where a spatial representation of a referent is required. Examples are image processing and machine vision. In image processing the “referents” are signal sources which are being viewed by an image processing sensor, eg CCD array. The image sources will be points in a scene, for example. Currently available image systems must be aware of the relative positions of the image sensors. In prior art image systems, this information is usually provided a priori. In the present invention, no a priori information on the arrangement of the image sensors is required. Instead, a geometrical representation of the referents is produced by obtaining signals from the referents and utilizing the signals in order to provide the geometrical representation. The geometrical representation is built up purely from the signals provided by the sensors themselves.