MOTOR VEHICLE EXHAUST CATALYST REGENERATION

摘要

The present invention relates to an apparatus and method of regenerating an aged motor vehicle exhaust catalytic converter. An internal combustion engine exhaust gas purification system (1) comprises: an internal combustion engine (2) having an exhaust conduit (4); an engine management system (8) with control means capable of controlling the engine air/fuel ratio (10) alternately at a super-stoichiometric level and at a sub-stoichiometric level, and a three-way catalyst (6) in-line with the exhaust conduit (4) and comprising noble metals selected from the platinum group and rhodium, the catalyst (4) exhibiting a three-way oxidising activity on the exhaust gases, and the efficiency of the three-way activity degrading over time when the engine (2) is operated at a super-stoichiometric level. The engine management system (8) also comprises timer (12) and memory (14) means to measure and store more than one cumulative time, including a first cumulative time over which the engine (2) is operated at the super-stoichiometric level and during which the efficiency of the three-way activity degrades, and also a second cumulative time over which the engine (2) is operated at a sub-stoichiometric level, the alternation between levels being such that the first cumulative time is greater than the second cumulative time, and the second cumulative time is sufficient to regenerate at least partially the efficiency of the three-way activity.