Considerable work has been carried out to develop particulate control systems for light duty vehicles. These systems are required to operate under widely varying conditions of service. Examination of the extremes of operation shows the importance of the regeneration ability of the control system employed. In addition, a major requirement for a practical control system is minimum complexity.Discussed here is a catalyst system and the extension of the technology to allow for minimum complexity and the ability to operate at the defined extremes of use. The theory of the TRIM System and the results of evaluations on vehicles and test benches are given.