State Key Laboratory of Internal Combustion Engines

With the diesel particulate filter more and more widely applied on engine, the particulate matter (PM) sensor is used to detect malfunctions of diesel particulate filter (DPF) in on board diagnostics (OBD). This paper focused on the new leakage current particulate matter sensor, which has more practical significance. The electric field and flow field were simulated by the COMSOL Multihysics, and the influence rules of sensor electrode parameters on the electric field and flow field were analyzed. The dynamic characteristics of particulate matters with different charges was studied. The simulation results showed that the average electric field strength was higher with higher electrode voltage and larger electrode spacing, which made the motion trend of charged particulate matter to electrodes more obvious. The decrease of electrode spacing or the increase of electrode length made the exhaust flow more stable, and the motion trend of charged particulate matters to electrodes is more obvious with the increase of electrode length. It was concluded that the flow of the exhaust and particulate matter was in good condition when the electrode spacing was 12.5mm, the electrode length is 12.5mm and the electrode voltage ranged between 1000V and 1500V.

Gasification of corn cob and crude glycerol and pure glycerol in the fixed-bed reactor were carried out. The effect of crude glycerol and pure glycerol on the gasification gas component trends was studied in detail. The resulted show that the crude glycerol has little influence on the trends of gas component, when the pure glycerol/raw material is larger than 20%, the trends of syn-gas and CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> change dramatically than that of crude glycerol. Meanwhile Aspen Plus software was used on the experimental cases, and the results show that the model can give a very good prediction for co-gasification process of biomass and glycerol.

The long-term vibration of the carbon canister during vehicle operation can lead to changes in its performance, thereby affecting its performance on evaporation emissions. A vibration test bench simulating vehicle vibration characteristics is used to simulate the working state of the carbon canister under actual driving conditions, analyze the amount of carbon powder precipitation and flow resistance changes in the canister after long-term operation, and compare the adsorption and desorption performance of the canister before and after aging and their effect on the evaporative emissions. The results showed that the carbon canister will produce carbon powder precipitation after being continuously subjected to the forward and backward vibration of the vehicle. This leads to a decrease in the ultimate adsorption and desorption capacity of the aged carbon canister for fuel vapor, with a more significant decrease in adsorption capacity. However, in the 2-day Diurnal Breathing Loss(DBL) test, due to the increase in flow resistance of the aged carbon canister, it is more difficult for the adsorbed fuel vapor to diffuse outward. For the unsaturated carbon canister, fuel leakage and evaporative emissions can be reduced. In evaporative emission management, it is necessary to adjust the control strategy reasonably based on the working status of the carbon canister.

To address the challenges faced by vehicles during actual operation when passing through traffic lights or intersections, where rapid changes in operating conditions can lead to a decrease in SCR efficiency and an increase in NOx emissions, this study focuses on defining characteristic position scenarios and analyzing the NOx emission characteristics of vehicles when passing through these scenarios based on real-time vehicle conditions. Through the analysis of several specific events, several road condition factors and driver behavior factors that may contribute to increased NOx emissions at characteristic position scenarios are identified. The findings indicate that when vehicles pass through traffic lights and intersections, the main causes of increased NOx emissions are low SCR temperature resulting from prolonged idling or engine shutdown, and high exhaust NOx emissions resulting from sudden excessive fuel injection. The driver behaviors associated with these situations primarily include coasting when approaching intersections, frequent stop-start behaviour due to traffic congestion or road crowding, choosing to shut off the engine for fuel efficiency during prolonged traffic congestion, and aggressive acceleration by stepping on the accelerator when the green light is about to turn red.