Abstract: An exhaust after-treatment system for an internal combustion engine is provided having an exhaust passage in fluid communication with the exhaust manifold of the engine. A turbocharger coupled to the exhaust passage is operatively driven by a first portion of exhaust gases exiting the exhaust manifold. A bypass line is disposed parallel to the turbocharger, and fluidly coupled to the exhaust passage upstream and downstream of the turbocharger. The bypass line receives a second portion of the exhaust gases exiting the exhaust manifold. A fuel injector disposed in the bypass line injects a pre-determined amount of fuel in the bypass line to the second portion of the exhaust gases. An exhaust after-treatment module located downstream of the turbocharger and the bypass line receives the mixture of the first portion and the second portion of the exhaust gas.

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.

Abstract: An exhaust system includes an catalytic oxidation device, an particulate trap, a mixer, and a selective reduction catalyst (SCR), an adapter, and a sensor. The SCR is disposed downstream of a mixing tube and reduces oxides of nitrogen in the exhaust gas stream. The oxides of nitrogen are reduced in presence of ammonia on the SCR. The exhaust system also includes an adapter with an inlet and outlet pipe. A sensor is disposed downstream of the SCR, between the inlet and outlet pipe. The sensor is configured to measure an amount of oxides of nitrogen in the exhaust gas stream. Further an ammonia oxidation (AMOX) catalyst is disposed, in the adapter, upstream of the sensor for oxidizing the residual ammonia that may slip through the SCR before the exhaust gas stream reaches the sensor.

Abstract: A system and method controls injection of a reductant agent in a selective catalytic reduction system. The system and method include an injector injecting the reductant agent to an exhaust system directing exhaust from a power system. A coolant system circulates coolant proximate to the injector. A coolant temperature sensor monitors a coolant temperature of the coolant. A controller adjusts the injection timing of the injector based at least in part on the coolant temperature.

Abstract: A system and method controls injection of a reductant agent in a selective catalytic reduction system. The system and method include an injector injecting the reductant agent to an exhaust system directing exhaust from a power system. A coolant system circulates coolant proximate to the injector. A coolant temperature sensor monitors a coolant temperature of the coolant. A controller adjusts the injection timing of the injector based at least in part on the coolant temperature.