This study investigated the emission characteristics of ultra.fine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engin...This study investigated the emission characteristics of ultra.fine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of （0.56-8.35）×10^8 cm^-3. The on-board measurement results illustrated that the ultra_fine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 ×10^6 cm^-3 and 2.7 ×10^7 cm^-3 under decelerating and idling operations and as high as 5.0×10^8 cm^-3 under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a ＂U＂ shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.展开更多
In order to alleviate the pressure of experi- mental research of turbocharged diesel engine under transient operations, a whole process simulation platform for turbocharged diesel engine under transient operations was...In order to alleviate the pressure of experi- mental research of turbocharged diesel engine under transient operations, a whole process simulation platform for turbocharged diesel engine under transient operations was established based on the multi-software coupling technologies of Matlab/Simulink, GT-Power, STAR-CD and artificial neural network. Aimed at the contradiction of NOx and soot emission control with exhaust gas recirculation （EGR） of turbocharged diesel engine under transient operations, on this simulation platform, a transient EGR valve control strategy was proposed, which adjusted the EGR valve in adjacent level based on the feedback of its opening according soot control limit under transient operations. Simulation and experimental results prove that the transient emission optimization effect of this control strategy is obvious. On the one hand, compared with the previous control strategy, which closed the EGR valve during the whole transient operations, soot emission is slightly increased by 9.5%, but it is still 9% lower than the control limit. On the other hand, compared with the previous control strategy, NOx transient emission is reduced by 44%.展开更多
基金supported the Instantaneous Emission and Environmental Impact study on Vehicle Alternative Fuel(No.10231201902)the Project of Study and Demonstration of Real Time On-Road Vehicle Emission and Pollution Warning (No.10231201700) from the Shanghai Science and Technology Commission
文摘This study investigated the emission characteristics of ultra.fine particles based on test bench and on-board measurements. The bench test results showed the ultrafine particle number concentration of the diesel engine to be in the range of （0.56-8.35）×10^8 cm^-3. The on-board measurement results illustrated that the ultra_fine particles were strongly correlated with changes in real-world driving cycles. The particle number concentration was down to 2.0 ×10^6 cm^-3 and 2.7 ×10^7 cm^-3 under decelerating and idling operations and as high as 5.0×10^8 cm^-3 under accelerating operation. It was also indicated that the particle number measured by the two methods increased with the growth of engine load at each engine speed in both cases. The particle number presented a ＂U＂ shaped distribution with changing speed at high engine load conditions, which implies that the particle number will reach its lowest level at medium engine speeds. The particle sizes of both measurements showed single mode distributions. The peak of particle size was located at about 50-80 nm in the accumulation mode particle range. Nucleation mode particles will significantly increase at low engine load operations like idling and decelerating caused by the high concentration of unburned organic compounds.
基金This work was supported by the National Basic Research Program of China （No. 2013CB228402） and the National Natural Science Foundation of China （Grant No. 50976046）.
文摘In order to alleviate the pressure of experi- mental research of turbocharged diesel engine under transient operations, a whole process simulation platform for turbocharged diesel engine under transient operations was established based on the multi-software coupling technologies of Matlab/Simulink, GT-Power, STAR-CD and artificial neural network. Aimed at the contradiction of NOx and soot emission control with exhaust gas recirculation （EGR） of turbocharged diesel engine under transient operations, on this simulation platform, a transient EGR valve control strategy was proposed, which adjusted the EGR valve in adjacent level based on the feedback of its opening according soot control limit under transient operations. Simulation and experimental results prove that the transient emission optimization effect of this control strategy is obvious. On the one hand, compared with the previous control strategy, which closed the EGR valve during the whole transient operations, soot emission is slightly increased by 9.5%, but it is still 9% lower than the control limit. On the other hand, compared with the previous control strategy, NOx transient emission is reduced by 44%.
