Experimental investigation on the emission reduction potential of metal oxide-coated ceramic foam filters as substrates for diesel engines

The applicability of ceramic foam filter as a honeycomb structure substitute to achieve a reduction in the amount of engine exhaust emitted from a diesel engine at various brake powers is tested and studied experimentally. Initially, ceramic foam filters were wash-coated in-house using metal oxides such as Aluminum Oxide (Al2O3), Copper Oxide (CuO), and Titanium Oxide (TiO2). The wash-coated ceramic foams were installed inside the outer casing of the Catalytic Converter (CC), which was fabricated in-house according to the dimensions of the CC manufactured by the Original Equipment Manufacturer (OEM). The CC manufactured by OEM consists of honeycomb monolith wash-coated with Platinum (Pt), Palladium (Pd), and Rhodium (Rh) as catalyst materials. The initial performance and emission tests were conducted using the manufactured CC. Following this, the experiments were conducted using ceramic foam-modified CC. The experimental results show that the brake thermal efficiency exhibited by the ceramic foam filter was less than that recorded for the honeycomb monolith substrate. At full load, the Brake Thermal Efficiency (BTE) of the OEM manufactured CC, ceramic foam filter-wash coated with Al2O3, CuO, and TiO2, were 33.14%, 31.6%, 30.2%, and 29.2%, respectively. Reduced emission output parameters, such as Hydrocarbon (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NOx) emissions, were recorded for the metal oxide-coated ceramic foam filter. The CO and HC conversion efficiencies observed for the ceramic foam filter were significantly higher than the efficiencies of the CC manufactured by OEM. The NOx conversion efficiency was marginally higher than that recorded for the manufactured CC.