The design and application of an underfloor gasoline particulate filter(GPF) and catalyzed gasoline particulate filter(CGPF) were carried out on a 1.6 litre

direct injection gasoline sedan. The effect of different wash-coat loadings

coating processes and precious metal contents on the cold flow back pressure and coating morphology of the GPF and CGPF systems were studied

and a low back pressure CGPF sample was designed accordingly. Through the worldwide harmonized light vehicles test cycle(WLTC) for gasoline vehicles according to the requirements of CN6 emission regulation

the effect of the underfloor GPF

CGPF and different precious metal contents on exhaust aftertreatment systems were investigated

respectively

by comparing with the emission performance of original close-coupled three-way catalytic converter. Results show that the addition of underfloor GPF or CGPF system downstream of the three-way catalytic converter increases the exhaust back pressure

but does not significantly increase the fuel consumption

which can effectively solve the problem of excessive PN caused by using three-way catalytic converter alone. At the same time

the use of CGPF system can better remove gaseous pollutants while ensuring particulate filtration efficiency

and make various emission indicators meet the requirements specified in CN6 emission regulation. Besides

Preconditioning of the CGPF system according to the WLTC procedure can effectively improve its particulate trapping ability

resulting in an increase of particulate filtration efficiency from 76.38% to 97.00%.