Abstract: Exhaust gas systems includes an oxidation catalyst (OC) capable of receiving exhaust gas and oxidizing one or more of combustable hydrocarbons (HC) and one or more nitrogen oxide (NOx) species, a selective catalytic reduction device (SCR) disposed downstream from and in fluid communication with the OC, an upstream NOx sensor disposed upstream from the SCR, and a downstream NOx sensor disposed downstream from the SCR. Methods for controlling systems include providing exhaust gas to the OC and subsequently the SCR, measuring an upstream exhaust gas NOx concentration, measuring a downstream exhaust gas NOx concentration, determining a NOx differential by subtracting the downstream exhaust gas NOx concentration from the upstream exhaust gas NOx concentration; and comparing the NOx differential to a differential threshold to determine OC catalytic performance. The method is conducted under while OC is above a NOx to NH3 conversion yield threshold, and/or under rich conditions.

Abstract: Exhaust gas systems includes an oxidation catalyst (OC) capable of receiving exhaust gas and oxidizing one or more of combustable hydrocarbons (HC) and one or more nitrogen oxide (NOx) species, a selective catalytic reduction device (SCR) disposed downstream from and in fluid communication with the OC, an upstream NOx sensor disposed upstream from the SCR, and a downstream NOx sensor disposed downstream from the SCR. Methods for controlling systems include providing exhaust gas to the OC and subsequently the SCR, measuring an upstream exhaust gas NOx concentration, measuring a downstream exhaust gas NOx concentration, determining a NOx differential by subtracting the downstream exhaust gas NOx concentration from the upstream exhaust gas NOx concentration; and comparing the NOx differential to a differential threshold to determine OC catalytic performance. The method is conducted under while OC is above a NOx to NH3 conversion yield threshold, and/or under rich conditions.

Abstract: A method and apparatus are disclosed for controlling the operation of an aftertreatment system for a motor vehicle having a Lean NOx Trap and a tail pipe for conveying exhaust gasses from the LNT to the external environment. Values are calculated for a NOx content in the exhaust gasses flowing in the tail pipe and the quantity of NOx stored in the LNT. A DeNOx request index is calculated as a function of these values. A raw threshold value of the DeNOx request index is calculated as a function of a LNT temperature and of an exhaust gas mass flow. A corrected threshold value of the DeNOx request index is calculated as a function of the raw threshold value of the DeNOx request index and of a correction factor. A DeNOx regeneration is initiated when the calculated value of the DeNOx request index is larger than the corrected threshold value.

Abstract: A method and apparatus are disclosed for controlling the operation of an aftertreatment system for a motor vehicle having a Lean NOx Trap and a tail pipe for conveying exhaust gasses from the LNT to the external environment. Values are calculated for a NOx content in the exhaust gasses flowing in the tail pipe and the quantity of NOx stored in the LNT. A DeNOx request index is calculated as a function of these values. A raw threshold value of the DeNOx request index is calculated as a function of a LNT temperature and of an exhaust gas mass flow. A corrected threshold value of the DeNOx request index is calculated as a function of the raw threshold value of the DeNOx request index and of a correction factor. A DeNOx regeneration is initiated when the calculated value of the DeNOx request index is larger than the corrected threshold value.

Abstract: A method of estimating a variation of a quantity of soot accumulated in a diesel particulate filter coupled to an internal combustion engine is provided. The method includes a passive-regeneration check for checking whether a passive regeneration of the diesel particulate filter is occurring and, if this check yields that a passive regeneration is actually occurring, the method includes determining an initial quantity of soot that was accumulated in the diesel particulate filter when the passive regeneration began and determining a rough variation of the quantity of soot accumulated in the diesel particulate filter. An engine speed and an engine load are determined and, using the engine speed, the engine load, and the initial quantity of soot, a correction is determined. The variation of the quantity of soot accumulated in the diesel particulate filter is calculated as a function of the rough variation and the correction.

Abstract: A method and apparatus for controlling a diesel particulate filter is disclosed. The control is carried out with the aid of a soot loading model selected from a plurality of available soot loading models including at least one soot loading physical model which makes use of signals from an exhaust gas pressure sensor. A reliability score is allocated to each soot loading model such that the soot loading model with the best reliability score is used for the diesel particulate filter control. If a DPF parking effect is identified based on an engine shut-off time a DPF inlet temperature either the reliability score of the soot loading physical model or the reliability scores of all remaining (non-physical) soot loading models are changed, and use of the soot loading physical model is avoided or disabled to help the control of the diesel particulate filter.

Abstract: A method of estimating a variation of a quantity of soot accumulated in a diesel particulate filter coupled to an internal combustion engine is provided. The method includes a passive-regeneration check for checking whether a passive regeneration of the diesel particulate filter is occurring and, if this check yields that a passive regeneration is actually occurring, the method includes determining an initial quantity of soot that was accumulated in the diesel particulate filter when the passive regeneration began and determining a rough variation of the quantity of soot accumulated in the diesel particulate filter. An engine speed and an engine load are determined and, using the engine speed, the engine load, and the initial quantity of soot, a correction is determined. The variation of the quantity of soot accumulated in the diesel particulate filter is calculated as a function of the rough variation and the correction.