Development works with metallic open channel PM Filter Catalyst in conjunction with diesel oxidation catalysts and Pre Turbo Catalyst (PTC) on Diesel Cars and Commercial Vehicles with CRDi engines have been reported earlier. These results show that PM conversion efficiency of the order of 40 % can be achieved with PM Filter Catalyst on passenger car diesel engines with continuous regeneration capability.
Recently experiments were carried out on a DI engine having distributor type rotary fuel injection equipment with electronic control, turbocharged and inter-cooled, calibrated for BS-III (EURO-III) emissions, with an aim to explore the potential of oxidation catalyst and the PM Filter Catalyst to meet BS-IV (Euro-IV) emission norms. These experiments were carried out with 500ppm sulphur diesel. The results of the tests are presented in this paper. It is seen that with only an oxicat of low level catalyst loading, PM (soluble organic fraction) can be brought down by 20%.
PM Filter Cat needs high percentage of NO2 to regenerate itself. Due to high sulphur fuel, oxicats with higher catalyst loading form sulphates and prohibit oxidation of NO to NO2. Thus the potential for major PM reduction with the help of metallic PM Filter Cat cannot be realized with high sulphur fuel.
Experiments with 50 ppm sulphur diesel could not be arranged to find out the effectiveness of the system for its applicability for BS-IV. The same is planned in near future.