Abstract: A method for operating a vehicle having a fuel system that may include unwanted water is described. The method includes, adjusting an operating parameter in response to a relative amount of high and low readings from a water-in-fuel sensor coupled in the fuel system.

Abstract: Methods for updating the PF soot load of an engine are provided herein. In one example, a soot storage estimate is based on processing operations that occur at different timings. The method can improve soot estimation during some conditions.

Abstract: Systems and methods for updating the PF soot load of an engine are provided herein. In one embodiment, the method may include performing regeneration in response to both pressure-based measurements as well as estimated soot loading independent of the pressure-based measurements, where during conditions in which the pressure-based measurements may be inaccurate, the soot load is estimated based on operating conditions and previous pressure-based measurements that occurred during previous conditions in which the pressure-based measurements are more accurate. In this way, more continuous monitoring of particulate filter loading is provided, while taking advantage of pressure-based measurements from the most recent accurate reading, for example, and operating conditions that have transpired since such reading, including transient conditions. Thus, more appropriately timed regeneration may be provided.

Abstract: A method for operating a vehicle having a fuel system that may be contaminated with water is described. The method includes, adjusting an operating parameter in response to a relative amount of high and low readings from a water-in-fuel sensor coupled in the fuel system.

Abstract: A method is presented for controlling fuel tank pressure in an internal combustion engine. The engine, the fuel tank and the carbon canister are connected in a three-way connection. The engine can be selectively isolated by a purge control valve, and the fuel tank can be selectively isolated by a fuel tank control valve. The operation of both valves is coordinated by an electronic engine controller. By isolating the fuel tank during the carbon canister purge, vapor spikes into the engine are eliminated, thus preventing engine stalls. Also, canister durability is improved by continuously storing and purging vapors in opposite directions.

Abstract: An engine controller tracks purge system pressure within a vapor line extending from a fuel tank to a carbon canister and, in the event that pressure changes at an unduly high rate, operates to restrict the purging of vapor from a carbon canister.

Abstract: A method and system for determining a level of vapor generated by an evaporative system. The evaporative system is closed to atmosphere. An initial pressure in a fluid-filled tank is sensed and, after a predetermined amount of time, a second pressure in the tank is sensed. A pressure difference is determined based on the sensed initial pressure and the sensed second pressure. The level of vapor generated by the evaporative system is determined based on the pressure difference.