【作者】 向禹；

【导师】 颜伏伍；

【作者基本信息】 武汉理工大学 ， 动力机械及工程， 2006， 硕士

【摘要】 电子控制技术是降低发动机排放污染,提高其动力性和经济性的一个重要手段。为了使发动机满足国家的排放法规,获得较好的动力性和经济性能,保持良好的工作稳定性,需要对发动机电控系统与发动机进行匹配,对控制参数进行标定和优化。从匹配标定技术的发展来看,局部优化与全局优化相结合、在线标定、自动标定系统和瞬态标定系统是今后的发展方向。 本文以国内应用广泛的491QE汽油发动机为研究对象。首先,分析了电控系统匹配标定的约束条件。发动机匹配标定的基本目标是在满足排放法规的基础上,提高燃油经济性,获得较好的动力性能和驾驶性能。其次,分析了电控系统的控制策略,包括空燃比控制和点火提前角控制。对燃油定量采用了速度一密度法,空燃比控制分为开环控制和闭环控制。对点火提前角的控制主要是开环控制,控制数据由试验得到,对爆震现象采取了闭环控制。在以上分析的基础上,提出了针对491QE发动机的匹配标定方案。 在试验过程中,建立了电控系统的集成开发环境,包括发动机工况控制、传感器信号采集、排放性能测试、ECU控制参数采集和试验数据分析处理等子系统。通过ECU与计算机、计算机与计算机之间的数据通讯和共享,可以实行电控系统的在线标定和自动标定。 试验中首先对491QE发动机的稳态工况进行了标定。通过对事先划分的工况点的逐点实现,以λ闭环控制为目的,得到了基本喷油脉宽和基本点火提前角。通过改变试验环境,得到了喷油脉宽和点火提前角对进气温度、冷却水温度和蓄电池电压变化的修正系数。对λ闭环控制控制过程中氧传感器电压阈值调节和λ调节进行了初步分析。 在稳态标定的基础上,对冷起动和暖机工况、怠速工况、加减速工况、功率加浓等过渡工况进行了分析,提出了控制方法并进行了相关试验,得到了控制参数。试验结果表明,匹配标定后的发动机获得了良好的排放性、经济性和动力性能。更多还原

【Abstract】 Electronic Engine Control is an important method to reduce the engine emissions and improve power and economic performance. It is necessary to match the Electronic Control System with the engine and to optimize and calibrate the control parameters in order to meet the China Emission Standard and get better power and economic performance. Local optimization integrated with global optimization, on-line calibration, automatic calibration and transient state calibration are promising methods for calibration and optimization of the Electronic Control System for automotive engine.This paper takes the popular used 491QE gasoline engine as research object. Firstly, the restriction of matching and calibration is analyzed. The basic purpose of engine matching and calibration is to improve economic performance and to obtain good power performance and drivability based on meeting the China Emission Standard. Secondly, the control strategy of Electronic Control System is analyzed, including fuel-air ratio control and ignition advance angle control. Speed-density method is applied to fuel fix quantity and the fuel-air ratio control includes open-loop control and close-loop control. The control of ignition advance angle is mostly open-loop control and the control data is obtained from experiment. Close-loop control method is applied to avoid engine knock. Finally, a procedure of matching and calibration for 491QE gasoline engine is made on the basis of analysis above.An integrated development environment of Electronic Engine Control is established during the test trip, including engine operation controlling, sensor signals collecting, emission performance testing, ECU control parameters collecting, data analyzing and other subsystems. It is easy to accomplish the on-line and automatic calibration of electronic control system by communicating and sharing the data between the ECU and the Up-PC.The calibration of steady state for 419QE gasoline engine is finished firstlyduring the test trip. Aiming on X close-loop control, by completing the state points plotted before, the map of base fuel inject pulse width and base ignition advance angle are obtained. The modification coefficient of fuel inject pulse width and ignition advance angle caused by intake air temperature, coolant temperature and storage battery voltage are obtained by changing test environment. The adjustments of exhaust gas oxygen sensor voltage threshold value and fuel-air ratio during the X close-loop control process are introduced as well.Based on steady state calibration, the cold start and warm up operation, idle speed, acceleration and deceleration, power enrichment and other transient states are analyzed. The control way is introduced and the control parameters are obtained. The final results show that the system performed very well.更多还原