Abstract: A method for improving NOx conversion efficiency of a Nox-reducing catalyst by determining an accurate amount of reductant required is presented. The method includes calculating an initial reductant injection amount based on a steady state amount of NOx in the engine feedgas and adjusting the initial amount to compensate for transient NOx emissions. The compensation is initiated in response to an engine transient, such as impending acceleration or deceleration. This method further results in improved vehicle fuel economy.

Abstract: A method for improving NOx conversion efficiency of a NOx-reducing catalyst by determining an accurate amount of reductant required is presented. The method includes calculating an initial reductant injection amount based on a steady state amount of NOx in the engine feedgas and adjusting the initial amount to compensate for transient NOx emissions. The compensation is initiated in response to an engine transient, such as impending acceleration or deceleration. This method further results in improved vehicle fuel economy.

Abstract: A method for improving NOx conversion efficiency of a NOx-reducing catalyst by determining an accurate amount of reductant required is presented. The method includes calculating an initial reductant injection amount based on a steady state amount of NOx in the engine feedgas and adjusting the initial amount to compensate for transient NOx emissions. The compensation is initiated in response to an engine transient, such as impending acceleration or deceleration. This method further results in improved vehicle fuel economy.

Abstract: A diesel engine equipped with an exhaust gas particulate filter includes a control system that reduces exhaust gas smoke emissions normally resulting from an extended period of engine idling. The control method periodically raises the exhaust gas temperature in order to purge the particulate filter of water and hydrocarbons that build up during extended engine idling and cause exhaust smoke. A timer records the elapsed period during which the engine remains at idle and the exhaust temperature is below a threshold level. When the recorded time period exceeds a preselected value, the filter is purged by elevating the exhaust gas temperature to a level sufficient to oxidize the gaseous hydrocarbons and evaporate any water that may have accumulated in the filter.

Abstract: A method is described for preventing early degradation of an exhaust treatment device installed in a diesel powered vehicle, the treatment device having an active element located within a casing by means of a mat surrounding the active element. The method comprises temporarily operating the engine at an early stage following the installation of the exhaust treatment device in an alternative mode wherein the temperature of the exhaust treatment device is raised sufficiently to cause the mat surrounding the active element of the exhaust treatment device to pop.

Abstract: A filter used to remove particulates from a diesel engine exhaust is regenerated by increasing the exhaust temperature to achieve burn off of the accumulated particulates. Regeneration of the filter is inhibited when the sensed level of fuel in a diesel fuel tank for the engine falls below a first threshold level. Optionally, filter regeneration may be initiated when the sensed fuel level is between the first threshold and a higher threshold, and the load level of particulates accumulated in said filter is above a preselected, relatively high load level. Increase of the exhaust temperature to achieve burn off may be achieved by a variety of techniques, including throttling the intake of said engine, reducing the oxygen content in the exhaust gases delivered to said engine, closing an EGR valve of said engine, or performing post injection of fuel in the engine's combustion cylinders.

Abstract: A filter used to remove particulates from a diesel engine exhaust is regenerated by increasing the exhaust temperature to achieve burn off of the accumulated particulates. Regeneration of the filter is inhibited when the sensed level of fuel in a diesel fuel tank for the engine falls below a first threshold level. Optionally, filter regeneration may be initiated when the sensed fuel level is between the first threshold and a higher threshold, and the load level of particulates accumulated in said filter is above a preselected, relatively high load level. Increase of the exhaust temperature to achieve burn off may be achieved by a variety of techniques, including throttling the intake of said engine, reducing the oxygen content in the exhaust gases delivered to said engine, closing an EGR valve of said engine, or performing post injection of fuel in the engine's combustion cylinders.

Abstract: A diesel engine equipped with an exhaust gas particulate filter includes a control system that reduces exhaust gas smoke emissions normally resulting from an extended period of engine idling. The control method periodically raises the exhaust gas temperature in order to purge the particulate filter of water and hydrocarbons that build up during extended engine idling and cause exhaust smoke. A timer records the elapsed period during which the engine remains at idle and the exhaust temperature is below a threshold level. When the recorded time period exceeds a preselected value, the filter is purged by elevating the exhaust gas temperature to a level sufficient to oxidize the gaseous hydrocarbons and evaporate any water that may have accumulated in the filter.

Abstract: A method is described for preventing early degradation of an exhaust treatment device installed in a diesel powered vehicle, the treatment device having an active element located within a casing by means of a mat surrounding the active element. The method comprises temporarily operating the engine at an early stage following the installation of the exhaust treatment device in an alternative mode wherein the temperature of the exhaust treatment device is raised sufficiently to cause the mat surrounding the active element of the exhaust treatment device to pop.