Concern over particulate emissions from underground diesel engines initiated research into catalytic control of diesel exhaust in the early 1970’s. Fundamental laboratory investigations established the novel concept that suitable surface catalysis could initiate ignition of trapped particulate below the thermal ignition temperature. Catalyst compatible filter structures were developed and evaluated on bench engines and by engine users.
The later need for a compact, mass producible system to meet future automotive requirements lead to the development of a road going catalytic trap system. The parameters that affect catalytic particulate control are quantified. Ancillary control and operating systems required are discussed together with details of test data and durability experience obtained on bench tests and road going test fleets.