Abstract:
A method of controlling NO x emissions in an internal combustion engine is proposed, wherein the engine comprises an exhaust system with oxidation - promoting catalyst means (22) having a NO oxidation efficiency, and wherein the engine is normally operated on a map of normal EGR rates. The engine is operable in a NO 2 -promoting mode that comprises the steps of: determining whether operating the engine under a modified EGR rate would lead to an increased generation of NO 2 , said determination taking into account the variability of the NO oxidation efficiency with the oxidation temperature and the exhaust flow rate; and using the modified EGR rate for engine control in case it leads to an increased NO 2 generation.
Abstract:
A method of controlling combustion in an internal combustion engine with exhaust after treatment device is proposed, wherein upon detection of a request for a regeneration event of the exhaust after treatment device, a regeneration combustion mode comprising a pilot injection and a retarded main injection is operated. During the regeneration combustion mode the injection timing of the main injection is controlled so that its retard is not later than a retard threshold that is determined as the maximum timing retard to provide the desired torque, but with an injected fuel quantity not exceeding a maximum fuel quantity given by a stored smoke-limit map.
Abstract:
A method for controlling a selective catalytic reduction catalyst in an exhaust line of an internal combustion engine is disclosed, wherein the supply of a quantity of a gaseous ammonia reductant to the SCR catalyst uses a closed-loop SCR catalyst model coupled to a SCR-out NOx sensor that measures a SCR-out NOx emission value. The closed-loop SCR catalyst model uses a relationship linking the measured SCR-out NOx value to the NOx conversion efficiency and the ammonia slip. The actual NH 3 emission value and/or an actual SCR-out NOx indicative value are computed based upon differentiation of said relationship.
Abstract:
A method of controlling combustion in an internal combustion engine with exhaust after treatment device is proposed, wherein upon detection of a request for a regeneration event of the exhaust after treatment device, a regeneration combustion mode comprising a pilot injection and a retarded main injection is operated. During the regeneration combustion mode the injection timing of the main injection is controlled so that its retard is not later than a retard threshold that is determined as the maximum timing retard to provide the desired torque, but with an injected fuel quantity not exceeding a maximum fuel quantity given by a stored smoke-limit map.
Abstract:
There is presented a method for monitoring an oxidation catalyst in an exhaust line of an internal combustion engine, wherein a catalyst diagnostic event comprises a test cycle during which a conversion capability of the oxidation catalyst is determined based on the exotherm generated by post-injection of fuel. The diagnostic event may only be initiated when the temperature of the oxidation catalyst lies within a predetermined temperature range.