Hybrid vehicle power management modeling and refinement

The power management strategy in many hybrid vehicles is based on expert rules and thresholds. These rule-based strategies can result in good efficiency in term of fuel economy and emissions if their thresholds and rules are accurate. However, due to the complexity and the non-linearity of the hybrid powertrain, determining accurate thresholds and rules is neither explicit nor straightforward, and experts in most cases fail to define these thresholds and rules with enough accuracy. Based on this fact, the objective of this paper is to propose a method to improve this rule-based strategy by refining its thresholds and rules. To achieve this, we used an optimization method (dynamic programming) to calculate the optimal power management, determine the optimal control signals, and extract efficient thresholds and rules that can be used in real time. Finally, simulation results for the three strategies (optimal, simple and refined strategy) are shown and discussed.     

基于动态规划的混合动力商用车能量管理策略优化

考虑混合动力商用车部件基本的动态特性,在Matlab/Simulink中建立了整车前向仿真细化模型.应用动态规划理论获得整车燃油经济性的最优控制策略,包括能量分配和换挡控制策略.基于动态规划的最优控制策略,抽取出能够应用于实车控制的改进规则作为控制策略.采用重型车辆实际行驶工况的仿真结果表明,基于动态规划优化方法改进的整车控制策略可显著提高燃油经济性.     

加筋高性能砂浆加固RC梁抗弯性能及承载力计算

为统一中国对加筋高性能砂浆加固RC梁抗弯性能的认识,以中国学者所做95根加筋高性能砂浆加固的钢筋混凝土梁抗弯性能试验研究为基础,分析加固粱的受力性能和破坏机理,在此基础上考虑一次受力、二次受力、持载程度、加固筋类型、加固筋数量、混凝土强度等级等因素影响,建立加固梁抗弯承载力计算公式、刚度计算公式和裂缝宽度计算公式,并与试验数据进行了对比。结果表明：该加固技术采用高强钢绞线、钢筋网、钢丝网作为受力材料,虽然三者受力性能存在显著差异,但加固构件力学性能和破坏机理相似,可按统一计算公式进行承载力设计;公式计算值与试验结果符合良好,可用于实际工程计算。     

配备驻车加热器的柴油机冷起动性能改进

在低于-30℃的极端低温条件下,对装有驻车加热器的某柴油机进行了冷起动试验,并对其出现冷起动困难的原因进行了分析.研究发现,使用驻车加热器后对电控发动机ECU冷起动控制参数造成不利影响,并且与柴油机原有进气加热器未能实现合理的工作协调,对此提出了对电控系统硬件和软件控制策略进行改进的技术方案.经过改进和对冷起动控制参数进行重新标定后,该柴油机冷起动性能得到较大提高.     

高速磁浮线路系统公差预制检测体系

该文简要叙述高速磁浮线路复合梁技术的加工特点以及车间检测系统公差构成体系,同时分析了系统公差的检测布置点,提出了系统公差的分析方法。     

机场复合道面PCN计算方法分析

道面等级号(PCN)作为机场道面的主要技术参数,需要机场当局向外公布,随着我国旧机场道面补强工程的实施,如何计算复合道面的PCN是机场当局普遍面临的一个技术问题。该文以我国东部某国际机场跑道加铺工程作为实例,对复合道面PCN计算方法的选择、计算参数的选取、以及PCN的计算过程进行了详细的分析,对于类似工程道面PCN的计算具有一定的参考价值。     

车用柴油机微粒捕集器流场的数值模拟与分析

研究的柴油机微粒捕集器采用目前应用最为广泛的壁流式蜂窝陶瓷作为过滤体,根据其结构对称性和内部流动数学模型,建立了稳态层流的过滤体内部流动CFD仿真模型,并运用离散格式分离求解器进行求解。仿真计算与试验验证表明模型能准确反映过滤体内部流动特性。     

基于马尔可夫决策理论的燃料电池混合动力汽车能量管理策略

根据道路试验记录的数据建立驾驶员需求功率的马尔可夫模型,利用马尔可夫决策理论获得混合动力汽车的随机能量管理策略。借助燃料电池混合动力汽车控制系统的仿真平台进行仿真计算。北京公交车中速工况的仿真结果表明,与原先的恒电压控制策略相比,随机能量管理策略可以降低燃料消耗。     

水泥粉喷桩在软土地基处理中的应用

以四川某市的软土地基处理为例,对水泥粉喷桩加固软土地基的设计与施工、复合地基承载力和沉降等问题进行了探讨。     

Development of engine control using the in-cylinder pressure signal in a high speed direct injection diesel engine

Emission regulations are becoming more stringent and remain a principal issue for vehicle manufacturers. Many engine subsystems and control technologies have been introduced to meet the demands of these regulations. For diesel engines, combustion control is one of the most effective approaches for reducing not only engine exhaust emissions but also cylinder-by-cylinder variation. However, the high cost of pressure sensors and the complex engine head design for additional equipment present difficulties for manufacturers. In this paper, cylinder pressure-based engine control logic is introduced for a multi-cylinder high speed direct injection (HSDI) diesel engine. The time for 50% of the mass fraction to be burned (MFB50) and the IMEP are valuable for determining the combustion status. These two in-cylinder quantities are measured and applied to the engine control logic. Fuel injection timing is controlled to adjust the operating MFB50 to the target MFB50 using PID control logic, and the fuel injection quantity is controlled to adjust the measured IMEP to the desired IMEP. The control logic is demonstrated at steady state and during transient conditions and is applied to an NEDC mode test.