板式吸收塔优化设计研究与软件开发

以板式吸收塔系统的年总费用为目标函数，建立了优化设计数学模型，以吸收塔的液气比为决策变量，用单变量优化算法(菲波拿契法)求得最优解。用Visual Basic6．0开发出板式吸收塔优化设计软件。软件运行于Windows 9x系统，界面友好，操作方便。算列表明优化设计比常规设计节省生产成本。     

间歇精馏常规设计和优化设计的模型及算法

建立了板式间歇精馏塔在恒馏出液组成操作状况下常规设计及优化设计的数学模型。常规设计模型用数值方法编程求解，对二元理想及非理想溶液均适用。优化设计模型以间歇精馏系统年效益最大为优化目标，用菲波那契法求解单变量优化问题，用复合形法求解多变量优化问题。模型同时考虑对整个间歇精馏系统(包括塔主体、塔顶冷凝器及塔底再沸器)进行优化，更符合工程实际情况。求解模型可得到间歇精馏过程最优的一系列设计和操作参数(如理论板数，塔径，操作回流比，塔釜蒸发量，釜残液组成，冷凝器传热面积及冷却水出口温度，再沸器传热面积及加热蒸汽温度等)。算例表明，对恒馏出液组成间歇精馏单变量及多变量优化设计比常规设计分别提高年效益2．6％和18．9％。     

多效蒸发系统优化设计目标函数的建立与求解

建立了带有冷凝水闪蒸的并流多效蒸发系统优化设计新模型。该模型以整个蒸发系统的年总费用（包括加热蒸汽年费用、真空系统年费用以及蒸发器和各辅助设备的年折旧维修费用等）最小为优化目标,以生蒸汽压力、冷凝器真空度及各效有效传热温度痉为决策变量,提出一种新算法——复合形法嵌套拉格朗日乘子法和矩阵法求最优解。算例表明,生蒸汽压力、冷凝器真空度、价格参数和冷凝水闪蒸对优化结果影响显著,按新模型优化设计比常规设计可节省年费用16％左右。新算法对初值要求不高、收敛稳定性好、收敛速度快。     

基于虚拟温度法的间歇过程换热器网络综合

提出了基于时间段模型(TSM)综合间歇过程换热器网络的方法,用虚拟温度法代替传统的单一最小传热温差,将各流股的温差贡献值作为决策变量,年度总费用最小作为目标函数建立数学模型.应用遗传膜拟退火算法对上述数学模型进行求解,分别获得每个时间间隔内的子换热器网络结构,并进一步对总换热器网络做结构优化,使其既满足流股的换热要求,又满足年费用最小.方法应用于实例计算,结果比基于最小传热温差获得的换热器网络年度总费用节省6.0%,换热器减少5台,说明这种方法既节省费用,又简化了网络结构.     

两级系统多周期随机库存路径优化

库存和运输是物流活动的最主要环节,如何同时对二者进行优化,是供应商管理库存必须解决的核心问题。针对一个配送中心为多个零售商实施统一配送的两级系统,以最小化系统计划期平均总费用为目标,分析包括零售商存储费、缺货费,以及配送中心进货费、存储费和配送费的系统全部费用组成,整合库存与配送建立了库存路径问题数学模型。根据零售商需求的随机性和库存路径问题本身的两阶段性,估计零售商库存上下限,选择配送中心订货策略及配送优先原则,借鉴旅行商问题求解思路,设计了求解问题的启发式算法。用Matlab7.0编程实现仿真算例求解表明,整合优化比分别优化节省平均总费用6.2%。     

煤制气托普索甲烷化工艺热力学分析

利用化工流程模拟软件Aspen Plus,对煤制气托普索甲烷化工艺第一级带循环回路的反应系统进行了模拟研究。考察了在恒温条件下,反应器的温度、压力、循环比、水蒸气比对反应器出口甲烷含量和热负荷的影响:在绝热条件下,反应器的压力、循环比、水蒸气比对反应器出口温度和甲烷含量的影响。结果表明,在恒温条件下,除循环比外各因素对甲烷平衡含量都有影响,其中温度影响较大,温度越高,甲烷平衡含量越小;在绝热条件下,各因素对反应器出口温度和甲烷平衡含量都有影响,其中循环比影响较大,循环比越大,反应器出口温度越低,甲烷平衡含量越大,通过虚拟正交实验研究,得到各因素对反应器出口温度和甲烷含量的影响大小顺序为:循环比水蒸气比压力。     

石墨合成炉的结构及生产条件对合成气出口温度的影响

确定合成炉的出口温度是新型二合一氯化氢石墨合成炉优化设计的前提,本文从合成炉结构特点入手,提出确定气体出口温度的数学模型和计算程序,并通过Visual Basic 5.0编制的应用软件,研究了SSL-300～SSL-900型合成炉结构及生产条件对合成气出口温度的影响,结果是:不同型号的合成炉气体出口温度不同,在本文设计条件下,分别为260℃、236℃、245℃、321℃、343℃、368℃、418℃;气体出口温度随着原料气中氯气纯度或氯氢气量比的升高而降低;原料气温度的变化几乎对合成气出口温度没有影响;相同型号的合成炉,合成气出口温度随着冷却水温度的升高而增加。该项研究为优化设计新型的二合一氯化氢石墨合成炉提供了理论依据。     

部分热集成变压精馏分离酚焦油裂解产物过程模拟与优化

由于酚焦油裂解产物中,苯酚-苯乙酮体系的共沸组成对压力变化敏感,提出了变压精馏分离苯酚-苯乙酮共沸体系的新工艺,选择UNIQUAC物性方法,根据变压精馏原理确定了高、低压塔间循环物流的流量,用Aspen Plus软件对该工艺流程进行了模拟,提出了ASPEN Plus中精馏塔参数优化的通用方法,从而获得了各塔的最优参数。通过对模拟结果的分析,提出以高压塔的塔顶蒸汽为低压塔的塔釜热源的热集成新工艺,并将该工艺所需能耗和年度总费用与常规的变压精馏工艺相对比,结果表明高压塔冷凝水用量节省近2万吨/年,低压塔年度投入总费用降低约30%。     

油压减振器计算机辅助优化设计系统的研制

为了优化可调式线性油压减振器的性能，在白行研制的广义优化设计支持平台上对其线性阻尼系统进行广义优化建模与设计，并基于MATLAB开发了动态仿真软件包，对该广义优化设计结果进行分析与评价．样机开发与试验研究结果表明：文中建立的广义优化设计数学模型和动态仿真模型是准确的，研制的计算机辅助优化设计系统高效、实用．     

一种微波干燥控制系统的设计

设计了一种适用于果蔬等农产品微波干燥的反馈控制系统。详细论述了系统的实现原理及其功能模块,重点介绍了微波干燥单元、温度与功率控制单元、重量检测单元和上位机控制单元的设计思路和实现方法。应用纯净水加热实验对改造后的家用微波炉的输出功率进行标定,基于实验数据建立了微波功率与控制电压间的数学模型。以生姜为样本开展恒温干燥实验,结果表明本系统可实时记录温度、重量等数据,基于温度反馈控制能实现微波功率的连续、无级调节。     

Design and implementation of an autonomous EGR cooling system using deep neural network prediction to reduce NOx emission and fuel consumption of diesel engine

Neural Computing and Applications - This study includes the design of an autonomous exhaust gas recirculation (EGR) cooling system and implementation of the system on diesel engine by using deep...     

Nonlinear Observer-based Control Design and Experimental Validation for Gasoline Engines with Exhaust Gas Recirculation

This paper presents a nonlinear observer-based control design approach for gasoline engines equipped with exhaust gas recirculation (EGR) system. A mean value engine model is designed for control which includes both the intake manifold and exhaust manifold dynamic focused on gas mass flows. Then, the nonlinear feedback controller based on the developed model is designed for the state tracking control, and the stability of the close loop system is guaranteed by a constructed Lyapunov function. Since the exhaust manifold pressure is usually unmeasurable in the production engines, a nonlinear observer-based feedback controller is proposed by using standard sensors equipped on the engine, and the asymptotic stability of the both observer dynamic system and control dynamic system are guaranteed with Lyapunov design assisted by the detail analysis of the model. The experimental validations show that the observer-based nonlinear feedback controller is able to regulate the intake pressure and exhaust pressure state to the desired values during both the steady-state and transient conditions quickly by only using the standard sensors.     

电控EGR阀综合性能测试系统的研制

电控EGR阀是废气再循环技术中重要部件,主要包括步进电机式、电磁式和直流电机式,目前针对电控EGR阀测试系统研究尚不充分;为了实现对电控EGR阀各项技术指标的测试,研制了一套电控EGR阀综合性能测试系统;系统由驱动单元、控制单元、测试单元组成;驱动单元以电控EGR阀驱动器为驱动核心,控制单元以可编程控制器为控制核心,测试单元由各项指标的测试模块组成;通过对各项技术指标测试工艺流程设计,系统实现了对电控EGR阀流量特性、内漏性能、响应时间和阀内位置感应器性能的自动测试;实验结果表明,该系统稳定可靠,各项参数的机器能力指数Cmk均超过1.67,满足技术要求;系统提供了一种针对电控EGR阀综合性能的测试方案,并成功应用于某企业电控EGR阀生产测试车间。     

Quantitative feedback design of air and boost pressure control system for turbocharged diesel engines

For modern diesel engines, variable geometry turbocharger (VGT) is used to boost engine power output. In addition, exhaust gas recirculation (EGR) is utilized to reduce engine out NO_x emission. To realize these functions, a multivariable control system needs to control both VGT and EGR valve to deliver desired intake manifold (or boost) pressure, and desired EGR flow rate. This two-input and two-output system is nonlinear with cross-couplings between the boost and EGR responses to the input actuators, the system parameters are varying with different engine operating conditions. This paper proposes a closed loop design of a multivariable VGT/EGR control system for a turbocharged diesel engine. The control system is synthesized based on quantitative feedback theory to maintain robust stability and performance via sequential MIMO loop shaping in the frequency domain. Experiment results are included from a turbocharged diesel engine to show the effectiveness of the proposed control design.     

Neural Network Controller Development and Implementation for Spark Ignition Engines With High EGR Levels

Past research has shown substantial reductions in the oxides of nitrogen (NO_x) concentrations by using 10% -25% exhaust gas recirculation (EGR) in spark ignition (SI) engines (see Dudek and Sain, 1989). However, under high EGR levels, the engine exhibits strong cyclic dispersion in heat release which may lead to instability and unsatisfactory performance preventing commercial engines to operate with high EGR levels. A neural network (NN)-based output feedback controller is developed to reduce cyclic variation in the heat release under high levels of EGR even when the engine dynamics are unknown by using fuel as the control input. A separate control loop was designed for controlling EGR levels. The stability analysis of the closed-loop system is given and the boundedness of the control input is demonstrated by relaxing separation principle, persistency of excitation condition, certainty equivalence principle, and linear in the unknown parameter assumptions. Online training is used for the adaptive NN and no offline training phase is needed. This online learning feature and model-free approach is used to demonstrate the applicability of the controller on a different engine with minimal effort. Simulation results demonstrate that the cyclic dispersion is reduced significantly using the proposed controller when implemented on an engine model that has been validated experimentally. For a single cylinder research engine fitted with a modern four-valve head (Ricardo engine), experimental results at 15% EGR indicate that cyclic dispersion was reduced 33% by the controller, an improvement of fuel efficiency by 2%, and a 90% drop in NO_x from stoichiometric operation without EGR was observed. Moreover, unburned hydrocarbons (uHC) drop by 6% due to NN control as compared to the uncontrolled scenario due to the drop in cyclic dispersion. Similar performance was observed with the controller on a different engine.     

Extremum seeking-based optimal EGR set-point design for combustion engines in lean-burn mode

In lean combustion mode, exhaust gas ratio (EGR) is a significant factor that affects fuel economy and combustion stability. A proper EGR level is beneficial for the fuel economy; however, the combustion stability (coefficient of variation (COV) in indicated mean effective pressure (IMEP)) deteriorated monotonously with increasing EGR. The aim of this study is to achieve a trade-off between the fuel economy and combustion stability by optimizing the EGR set-point. A cost function (J) is designed to represent the trade-off and reduce the calibration burden for optimal EGR at different engine operating conditions. An extremum-seeking (ES) algorithm is adopted to search for the extreme value of J and obtain the optimal EGR at an operating point. Finally, a map of optimal EGR set-value is designed and experimentally validated on a real driving cycle.     

Motion planning for experimental air path control of a variable-valve-timing spark ignition engine

Air path control of a spark ignition engine without an EGR loop, equipped with variable-valve-timing (VVT) actuators, is addressed in this paper. VVT devices are used to produce internal exhaust gas recirculation, providing beneficial effects in terms of fuel consumption and pollutant emissions reduction. However, VVT actuators affect the fresh air charge in the cylinders. This has an impact on the torque output (leading to driveability problems) and on the fuel/air ratio (FAR) (leading to pollution peaks). To compensate for these undesirable effects, a new approach is proposed. Supportive experimental results show the relevance of this approach.     

Control of diesel engine dual-loop EGR air-path systems by a singular perturbation method

This paper presents a singular perturbation based method for controlling the dual-loop exhaust gas recirculation (DL-EGR) air-path systems on advanced diesel engines. A DL-EGR air-path system, consisting of a high-pressure loop EGR (HPL-EGR) and a low-pressure loop EGR (LPL-EGR), has significantly different time-scales (fast and slow) due to the inherent difference in the HPL-EGR’s and LPL-EGR’s corresponding control volumes. Such a feature of the DL-EGR systems makes the cooperative control of intake manifold gas conditions challenging. By considering the DL-EGR air-path system as a singularly perturbed system, a composite control law was devised to achieve systematic control of the air-path conditions including gas pressure, temperature, and oxygen fraction in the intake manifold. The effectiveness of the control method is experimentally evaluated on a medium-duty diesel engine.     

Real-time control oriented HCCI engine cycle-to-cycle dynamic modelling

For homogeneous charge compression ignition (HCCI) combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware-in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation (EGR) from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.