Abstract: A method for an exhaust after treatment system of an engine including at least one selective catalyst reaction (SCR), at least one clean up catalyst downstream from the SCR, a urea injector upstream of the SCR and a first NOx sensor downstream the clean up catalyst. The method includes the steps of injecting a predetermined amount of urea by the injector, providing a second NOx sensor between the SCR and the clean up catalyst, measuring the NOx content received by the first NOx sensor, measuring the NOx content received by the second NOx sensor, comparing the first and the second NOx content with each other, and reducing the predetermined amount of urea if the first NOx sensor measures a higher NOx content than the second NOx sensor.

Abstract: A method for an exhaust after treatment system of an engine including at least one selective catalyst reaction (SCR), at least one clean up catalyst downstream from the SCR, a urea injector upstream of the SCR and a first NOx sensor downstream the clean up catalyst. The method includes the steps of injecting a predetermined amount of urea by the injector, providing a second NOx sensor between the SCR and the clean up catalyst, measuring the NOx content received by the first NOx sensor, measuring the NOx content received by the second NOx sensor, comparing the first and the second NOx content with each other, and reducing the predetermined amount of urea if the first NOx sensor measures a higher NOx content than the second NOx sensor.

Abstract: An apparatus for treating engine exhaust gas includes comprising an exhaust conduit for leading exhaust gases from an engine to an outlet, a particulate filter connected in the exhaust conduit to receive exhaust gas, a heat source connected in the exhaust conduit upstream of the particulate filter, and, a heat exchanger connected to receive exhaust gas exiting the particulate filter and arranged to heat a portion of the exhaust conduit upstream of the heat source and particulate filter. Heating the exhaust gases prior to entry into the particulate filter helps ensure oxidation of the trapped particulate matter.

Abstract: An apparatus for treating engine exhaust gas includes comprising an exhaust conduit for leading exhaust gases from an engine to an outlet, a particulate filter connected in the exhaust conduit to receive exhaust gas, a heat source connected in the exhaust conduit upstream of the particulate filter, and, a heat exchanger connected to receive exhaust gas exiting the particulate filter and arranged to heat a portion of the exhaust conduit upstream of the heat source and particulate filter. Heating the exhaust gases prior to entry into the particulate filter helps ensure oxidation of the trapped particulate matter.

Abstract: A process for providing a real-time estimation of in-cylinder NOx production rates during a combustion process in an internal combustion engine. The process employs a model that takes into account fundamental in-cylinder variables such as temperature, pressure and oxygen content. The process can be used with calibrated or uncalibrated internal combustion engines and can be used to capture the effects in variations of engine speed, engine torque, EGR, injection timing, and engine boost levels.

Abstract: A process for providing a real-time estimation of in-cylinder NOx production rates during a combustion process in an internal combustion engine. The process employs a model that takes into account fundamental in-cylinder variables such as temperature, pressure and oxygen content. The process can be used with calibrated or uncalibrated internal combustion engines and can be used to capture the effects in variations of engine speed, engine torque, EGR, injection timing, and engine boost levels.