Abstract
In Renault exhaust system design methodology, a first short loop finds by calculations the best compromise between cost and conversion efficiency under architecture constraints. Then the chosen exhaust system is validated on chassis dynamometer.
In the Twingos case, the calculations work takes into account warm up strategies, thermal losses before the converter and its characteristics (volume, precious metal,...). A couple of exhaust systems which fulfils architecture constraints are selected and evaluated by calculation. Then, the best compromise is chosen. In this case, we go from a single under floor catalytic converter to a cascade one in the same location.
Thanks to this methodology, we save time in the development schedule. We also save money from all the test procedures.