Time filter

Source Type

Chen Z.,Hainan University | Li K.,Chinese Academy of Sciences | Liu J.,United Automotive Electronic System Co. | Wang X.,Hainan University | And 2 more authors.
Fuel | Year: 2015

A novel bio-fuel, glucose solution emulsified diesel, was evaluated for performance and emissions. To determine the effects of preparation conditions on the stability time of glucose solution emulsified diesel, an orthogonal experimental design L25(55) was used. According to the results of orthogonal experiment, a nonlinear regression model was constructed by response surface methodology (RSM) and optimized by the active set method. The stability time of glucose solution emulsified diesel was about 342 h under the optimal conditions of: 15% glucose aqueous solution, 2% emulsifier, 0.86% cosolvent, 20% glucose in solution and a hydrophilic and lipophilic balance (HLB) value of 5.58. The performance and emissions of emulsified diesel in a diesel engine was tested and compared with pure diesel. The results showed: that brake thermal efficiencies with emulsified diesel improved under partial loads at the speed of 2000 rpm, that NOx and smoke emissions with emulsified fuel decreased except at individual operating conditions, and that HC and CO emissions were different for the two fuels under different conditions. © 2015 Published by Elsevier Ltd. Source

Zhang G.,Shanghai JiaoTong University | Zhang G.,United Automotive Electronic System Co. | Hung D.L.S.,Shanghai JiaoTong University | Xu M.,Shanghai JiaoTong University
Experiments in Fluids | Year: 2014

Flash boiling sprays of liquid injection under superheated conditions provide the novel solutions of fast vaporization and better air-fuel mixture formation for internal combustion engines. However, the physical mechanisms of flash boiling spray vaporization are more complicated than the droplet surface vaporization due to the unique bubble generation and boiling process inside a superheated bulk liquid, which are not well understood. In this study, the vaporization of flash boiling sprays was investigated experimentally through the quantitative measurements of vapor concentration and liquid temperature. Specifically, the laser-induced exciplex fluorescence technique was applied to distinguish the liquid and vapor distributions. Quantitative vapor concentration was obtained by correlating the intensity of vapor-phase fluorescence with vapor concentration through systematic corrections and calibrations. The intensities of two wavelengths were captured simultaneously from the liquid-phase fluorescence spectra, and their intensity ratios were correlated with liquid temperature. The results show that both liquid and vapor phase of multi-hole sprays collapse toward the centerline of the spray with different mass distributions under the flash boiling conditions. Large amount of vapor aggregates along the centerline of the spray to form a "gas jet" structure, whereas the liquid distributes more uniformly with large vortexes formed in the vicinity of the spray tip. The vaporization process under the flash boiling condition is greatly enhanced due to the intense bubble generation and burst. The liquid temperature measurements show strong temperature variations inside the flash boiling sprays with hot zones present in the "gas jet" structure and vortex region. In addition, high vapor concentration and closed vortex motion seem to have inhibited the heat and mass transfer in these regions. In summary, the vapor concentration and liquid temperature provide detailed information concerning the heat and mass transfer inside flash boiling sprays, which is important for the understanding of its unique vaporization process. © 2014 Springer-Verlag Berlin Heidelberg. Source

Chen L.,Shanghai JiaoTong University | Zhu F.,Shanghai JiaoTong University | Zhang M.,University of Pittsburgh | Huo Y.,United Automotive Electronic System Co. | And 2 more authors.
IEEE Transactions on Vehicular Technology | Year: 2011

This paper describes the mathematical modeling, analysis, and simulation results of a novel electrical variable transmission (EVT) for a series-parallel hybrid electric vehicle (SPHEV). The proposed EVT uses a two-degree-of-freedom (2-DOF) planetary gearset with four clutches to combine an engine and two electric machines with the vehicle. The topology of the planetary gearset is the same as that of conventional four-speed automatic transmissions. Therefore, the proposed EVT can be mass-produced and quite easily packaged. Nine operation modes can be realized. The properly arranged clutches more flexibly transmit power flow and avoid high spin losses for the engine and electric machines. Simulation under the New European Driving Cycle (NEDC) drive cycle shows that the fuel consumption of the proposed SPHEV is 5.62% lower than a benchmark vehicle, which uses two planetary gearsets and no clutches, indicating the fuel economy potential of this concept. The life cycle of the electric machines is expected to be extended, because the open or locked operations of the clutches allow efficient operation and, thus, might reduce the chance of overheating. Finally, the speed range of the electric machines is found to be smaller, compared with that used in the benchmark vehicle, which implies ease of manufacture, good sustainability, and low cost. © 2011 IEEE. Source

Huang W.,Beijing Institute of Technology | Zhang Y.,Beijing Institute of Technology | Zhang X.,United Automotive Electronic System Co. | Sun G.,Beijing Institute of Technology
IEEE Transactions on Energy Conversion | Year: 2014

A novel parameters estimation strategy of interior permanent magnet synchronous machine (IPMSM) for accurate torque control is proposed and investigated in this paper. The difference of $q$-axis inductance and $d$-axis inductance is estimated by a PI regulator using the deviation between actual output power and reference power. The estimated difference of dq inductance can be used to achieve maximum torque per ampere control and accurate toque control. This strategy is most effective when IPMSM works under high-power high-speed working conditions. It provides an effective way for IPMSM accurate torque control. The effectiveness of the proposed method is verified by both simulation and experimental results. © 2013 IEEE. Source

Wang C.,United Automotive Electronic System Co. | Zhang L.,Tongji University
Qiche Gongcheng/Automotive Engineering | Year: 2011

The evaluation method of door closing sound quality based on time-frequency characteristics of A-weighted sound pressure level is presented with its virtues and defects pointed out. The computing models for Zwicker instantaneous loudness and time-varying loudness, Moore instantaneous loudness and time-varying loudness as well as sharpness are then built and their applicability to door closing sound quality evaluation is analyzed. Finally, a sound quality evaluation method for automotive door closing noise with the time-frequency characteristics of A-weighted sound pressure level, instantaneous loudness and sharpness as indicators is established and applied to the evaluation on two vehicle closing noise samples, and hence its feasibility is verified. Source

Discover hidden collaborations