Model for predicting the regeneration temperature of diesel particulate filter

The question of how to estimate diesel particulate filter (DPF) inner temperature distribution and peak temperature performance during DPF regeneration phase in diesel vehicle real-world application is a great challenge to many companies. The temperature prediction during DPF regeneration phase is directly related to the safety and economy performance of diesel engine after-treatment system and the vehicle. The temperature performance inside DPF during regeneration phase highly depends on the chemical reactions carried out inside diesel oxidation catalyst (DOC). According to the reaction mechanisms , reaction speed is related to the activation temperature of chemical reactions, carrier local wall temperature, and mole fraction of components involved in chemical reactions. In this paper, the temperature characteristics and their influencing factors were evaluated by means of one-dimensional simulation in combination with engine test bench validation. Firstly, main influencing factors to DPF regeneration temperature performance were analyzed. Theoretical analysis showed that when catalyst performance was already determined, DPF regeneration temperature performance were mainly affected by carrier local wall temperature and mole fraction of components involved in chemical reactions. Secondly, a one-dimensional after-treatment system model was built using GT-Power for DPF regeneration temperature prediction purpose, the influence of different regeneration target temperature on regeneration efficiency and the influence of different soot loading quantity on temperature distribution inside DPF during regeneration phase were analyzed. Simulation results showed that higher regeneration target temperature could benefit regeneration efficiency, and help to reduce fuel consumption of regenerating each gram of soot accumulated in DPF channels. When regeneration target temperature was 500 ℃, fuel consumption to regenerate each gram of soot would be 372.7 g. When regeneration target temperature was 550 ℃, fuel consumption would be 55.9 g. When regeneration target temperature was 600 ℃, fuel consumption would be 10.3 g. When regeneration target temperature was 650 ℃, fuel consumption would be 5.7 g. When regeneration target temperature was 700 ℃, fuel consumption to regenerate each gram of soot would be reduced to 3.8 g. However, higher target temperature had no obvious effect on the improvement of regeneration fuel consumption for each gram of soot when regeneration target temperature was higher than 600 ℃. According to the simulation result, when DPF soot loading quantity was higher than 46 g (12.7 g/L), the DPF inner temperature during regeneration phase would be higher than 800 ℃, leading to very high risk of DPF carrier burning crack, so soot loading quantity threshold for regeneration trigger should be well limited. Thirdly, regeneration temperature characteristics were tested on engine test bench. Test results showed that engine test bench results agreed well with simulation results when soot loading quantity were 15.5 and 21.9 g. Relative deviation with 15.5 g soot loading quantity was -1.0% to 0.4%, and relative deviation with 21.9 soot loading quantity was -1.4% to 0.8%. When soot loading quantity was 36.5 g, engine test bench result showed a different temperature ramping character for DPF tail position, the time to reach to maximum DPF inner temperature differed from simulation result, but still, the relative error of maximum temperature could be used for further investigation.