Gm Global Technolgoy Operations, Inc.

Giacomo Latrofa

Giovanni Montinaro

Giuseppe Schiavone

Raffaele Esposito

Fabrizio Ramolivo

Luisa Cusanno

Markus Hemm

Matteo Venturini

Barbara Maisola

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.

Methods for controlling and monitoring oxidation catalyst devices

A method and apparatus are disclosed for controlling the operation of an aftertreatment system for a motor vehicle having a Lean NOTrap and a tail pipe for conveying exhaust gasses from the LNT to the external environment. Values are calculated for a NOcontent in the exhaust gasses flowing in the tail pipe and the quantity of NOstored in the LNT. A DeNOrequest index is calculated as a function of these values. A raw threshold value of the DeNOrequest index is calculated as a function of a LNT temperature and of an exhaust gas mass flow. A corrected threshold value of the DeNOrequest index is calculated as a function of the raw threshold value of the DeNOrequest index and of a correction factor. A DeNOregeneration is initiated when the calculated value of the DeNOrequest index is larger than the corrected threshold value.

Method of controlling the operation of an aftertreatment system of a motor vehicle

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.

Method of estimating a variation of a quantity of soot accumulated in a diesel particulate filter

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Turin, Italy

Giacomo Latrofa