In order to analyze the reason for the improvement of the idle stability for a motorcycle engine when equipped with a secondary air compensating device, a model for the original engine is set up by the method of numerical simulation. The validation results of this model reveal relatively high simulation accuracy, and a model for the secondary air engine is established based on the previous model. The influence of secondary air on idle stability analyzed by using those simulation models, and the research reveals the main cause of idle instability for the original engine is that the residual gas fraction is too high. Based on valve timing, this research aims at finding a way to reduce residual gas fraction with relatively low influence on power performance for the original engine. The results indicate that the residual gas fraction for the original engine drops to the level of secondary air engine by advancing exhaust valve timing and the torque maximum value falls no more than 2%.
[1] Wong P K, Tam L M, Li K, et al. Engine idle-speed system modelling and control optimization using artificial intelligence[J]. Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering, 2010, 224(1):55-72.
[2] Kim D S, Cho Y S. Idle performance of an SI engine with variations in engine control parameters[J]. International Journal of Automotive Technology, 2006, 7(7):763-768.
[3] Kolodziej C, Ciatti S A, Kodavasal J, et al. Achieving stable engine operation of gasoline compression ignition using 87 AKI gasoline down to idle[C]//SAE 2015 World Congress & Exhibition, Detroit,USA:SAE International,2015.
[4] Xue J, Gao Q, Ju W.Reinforcement learning for engine idle speed control[C]//International Conference on Measuring Technology and Mechatronics Automation,March 13-14,2010. Changsha,China:IEEE, 2010:1008-1011.
[5] Patrick B, Oivind A, Per T, et al.The low load limit of gasoline partially premixed combustion using negative valve overlap[J].Journal of Engineering for Gas Turbines and Power, 2013, 135(6):1-7.
[6] Pielecha I, Cieślik W. Thermodynamic analysis of indexes of operation of the engine with direct fuel injection for idle speed and acceleration[J]. Journal of Thermal Analysis & Calorimetry, 2016, 126(2):815-827.
[7] Ji C, Wang S. Strategies for improving the idle performance of a spark-ignited gasoline engine[J]. International Journal of Hydrogen Energy, 2012, 37(4):3938-3944.
[8] Pinazzi P M, Foucher F. Influence of injection parameters, ozone seeding and residual NO on a Gasoline Compression Ignition (GCI) engine at low load[J].Proceedings of the Combustion Institute, 2016,36(3):3659-3668.
[9] 华国胜,何博.喷油时刻对摩托车发动机怠速稳定性影响的试验研究[J].小型内燃机与车辆技术,2017,46(2):43-45. HUA Guosheng,HE Bo. Research on the relationship between injection timing and motorcycle engine idle stability[J].Small Internal Combustion Engine and Vehicle Technique,2017, 46(2):43-45.(in Chinese)
[10] Liu C W, Ma E L, Yang Y X. Accurate control of air-fuel ratio for gasoline engine under idle speed condition[J]. Advanced Materials Research, 2012, 588-589:303-308.
[11] 邵千钧,何文华,熊树生.基于CMAC的点火提前角控制怠速稳定性的研究[J].内燃机学报,2005,23(4):376-379. SHAO Qianjun, HE Wenhua, XIONG Shusheng. Study on idling speed stability by spark advance angle controlling based on CMAC[J]. Transactions of Csice, 2005, 23(4):376-379.(in Chinese)
[12] Tsai H, Gao B Y, Chiang M H, et al. Misfire diagnostic strategy for motorcycles[J]. Papers; Automotive_Sector, 2013.
[13] Miki H, Kuwahara H. Approach combined numerical and experimental analysis for motorcycle engine radiation noise[C]//Small Engine Technology Conference & Exposition,United States:SAE International, 2006.
[15] Wu Y, Shen T, Bae C. Control design for residual gas fraction in engine based on stochastic logical dynamics[C]//Society of Instrument and Control Engineers of Japan,July 28-30,2015.Hangzhou,China:IEEE, 2015:1271-1275.
[16] Kodavasal J, Lavoie G A, Assanis D N, et al. Reaction-space analysis of homogeneous charge compression ignition combustion with varying levels of fuel stratification under positive and negative valve overlap conditions[J]. International Journal of Engine Research, 2015,17(7):1-19.
[17] Graf S, Linb T. Modeling fresh air charge and residual gas fraction on a dual independent variable valve timing SI engine[J]. Sae International Journal of Engines, 2008, 1(1):627-635.
[18] 吴颖军,黄丽娜,马文亮,等.气门重叠角对乘用车怠速抖动的影响[J].机械研究与应用, 2013, 26(3):79-82. WU Yingjun, HUANG Lina, MA Wenliang, et al. Effect of valve overlap angle on idling wobble of passenger car[J].Mechanical Research & Application, 2013, 26(3):79-82.(in Chinese)