Patent ID: 8327632

Claim:
An exhaust system for a lean burn internal combustion engine comprising: (a) a catalysed soot filter (CSF), comprising a catalyst; (b) a control unit; (c) means, controllable by the control unit, for increasing a content of combustible hydrocarbon (HC) and/or carbon monoxide (CO) in an exhaust gas flowing into the CSF thereby to combust the HC and/or CO in the CSF, to increase the temperature of the CSF and to combust particulate matter collected thereon; and (d) catalysed sensor means disposed between an engine manifold and the CSF for combusting CO and/or HC in exhaust gas flowing in the exhaust system and inputting the control unit with a datum correlating with an enthalpy of combustion of HC and/or CO in the exhaust gas, wherein the catalysed sensor means is the only catalysed component in the exhaust system disposed between the engine manifold and the CSF, whereby the control unit, when in use, controls the combustible HC and/or CO introducing means in response to the datum input thereby to control the content of the combustible HC and/or CO in the exhaust gas flowing into the CSF.