Based on engine test bench

the effects of platinum group metal(PGM) amount in DOC and exhaust temperature on the converting efficiencies of total hydro carbon(THC)

CO emission and T50(50% converting rate) temperature were investigated

and the gaseous pollutions converting performances of two DOCs(DOC1 and DOC2) with different PGM amount were obtained. The results show that for both DOCs

T50 temperatures for THC are 175℃ and 162℃

and for CO 149℃ and 151℃. When the exhaust temperature is higher than 220℃

the THC converting efficiencies of both DOCs are higher than 85%. When the exhaust temperature is over 190℃

the CO converting efficiencies of both DOCs are bigger than 95%. DOC1 is slightly better than DOC2 in terms of overall performance. Moreover

the effect of PGM amount on the temperature rise ability for DPF active regeneration at different engine operations and exhaust-pipe fuel injection rates was researched. The results indicate that the PGM amount and coating thickness can affect THC transform ability. DOC2 has higher PGM amount

transfers HC faster and is more sensitive to HC dosing. Therefore DOC2 rear temperature increases faster and more undulates. The PGM amount of DOC1 and DOC2 can ensure their rear temperatures to the target temperatures

and the rear temperatures become stable and the same at the end. In addition

the injection rate can affect DOC heating performance(heating rate). When the injection rate is below 40g/min

the heating rate of DOC2 is higher. When the injection rate is over 40g/min

the heating rate of DOC1 is higher. When the injection rate is 47.7g/min

the heating rates of DOC1 and DOC2 are 8.540℃/s and 7.401℃/s respectively

the difference is 15%.