Abstract: A fuel delivery system for an engine is provided. The fuel delivery system includes a fuel rail, a pressure sensor, a relief valve, and a controller. The controller is configured to receive a signal indicative of a fuel rail pressure, identify exceeding of the fuel rail pressure beyond a first threshold, identify the fuel rail pressure drop below a second threshold, and initiate a counter for a first predefined amount of time accordingly. The controller is also configured to identify if the fuel rail pressure drops below a third threshold within the first predefined amount of time, and identify if the fuel rail pressure remains below the third threshold for at least a second predefined amount of time. The controller is further configured to determine an open status of the relief valve based, at least in part, on the identification.

Abstract: A fuel delivery system for an engine is provided. The fuel delivery system includes a fuel rail, a pressure sensor, a relief valve, and a controller. The controller is configured to receive a signal indicative of a fuel rail pressure, identify exceeding of the fuel rail pressure beyond a first threshold, identify the fuel rail pressure drop below a second threshold, and initiate a counter for a first predefined amount of time accordingly. The controller is also configured to identify if the fuel rail pressure drops below a third threshold within the first predefined amount of time, and identify if the fuel rail pressure remains below the third threshold for at least a second predefined amount of time. The controller is further configured to determine an open status of the relief valve based, at least in part, on the identification.

Abstract: A method and a system for determining if fuel containing more than the desired concentration of sulfur is being combusted in an engine. The engine includes a selected catalytic reduction (SCR) module or a lean NOx trap (LNT) and the system includes various sensors and a controller for calculating NOx conversion ratio and ammonia slip. Timers are utilized for purposes of positively identifying when sulfur in the fuel is causing a substandard performance of the exhaust system. If the timers or time periods are not satisfied, a conversion ratio failure or an ammonia slip failure is attributable to equipment failure, and not sulfur in the fuel. However, if the timers are satisfied, then sulfur in the fuel is positively identified as the problem thereby enabling the operator to eliminate equipment failure as a possible source of the conversion ratio or ammonia slip failure.