Emissions performance of current TWC vehicles at low ambient temperature over FTP and ECE test cycles

The widening use of three-way catalyst for emission control has brought an increasing number of vehicles employnig this tehcnology also to the areas of cold climate, like the Nordic countries. However, cold operating environment is found to derate the performance of a TWC system, as the guidelines for its desing are mainly set by the legislation, in which the test procedures have not taken into account low ambient conditions. This set is about to change, as the United States has recently introduced a low temperature emissions test with CO standard. Similar evolution has already began also in Europe.