LJ465Q发动机可变长度进气系统的研究分析

为了研究可变进气系统对LJ465Q发动机动力性和经济性的影响,利用仿真软件GT-Power建立该发动机工作过程仿真模型,并进行发动机台架试验。经对比,试验值与仿真值吻合。在此基础上分析进气总管与进气歧管的不同管长方案对该发动机进气外特性、功率等的影响,提出一种发动机可变长度进气系统的研究方法并进行了试验验证。     

稀燃汽油机降低NO_x排放的数值模拟

为降低产品研发过程的技术风险,缩短研发周期,数值模拟已经成为发动机研发过程中的重要环节和手段。文章利用Simulink软件建立了一维稀燃汽油机LNT模型,同时利用STAR-CD软件建立了三维稀燃汽油机进气系统模型。研究了稀燃汽油机进气系统的仿真与优化,并探究了稀燃吸附还原催化器LNT的性能。数值模拟技术能够在发动机设计的整个过程中发挥重要的作用,是现代内燃机技术研究不可或缺的重要技术手段。     

汽油车进排气系统降低噪声研究

提出了一种汽油车进、排气系统降低噪声方法,并基于Helmholtz共振原理,利用三维CAD软件Pro/E设计了进气谐振消声器。利用GT-power软件建立了整车、发动机、进气谐振器、排气消声器的联合模型。根据发动机工作过程,对排气消声器进行了改进设计。试验结果表明,采用进气谐振器和改进后的排气消声器,能够降低汽车加速行驶车外噪声以满足要求,且基本保持汽车输出功率不变。     

基于WAVE的某增压汽油发动机进气系统噪声分析及优化

文章基于WAVE软件建立某增压发动机工作过程及进气系统仿真模型,后对该发动机进气系统进行一维噪声分析,并在此基础上通过增加相应的消声装置对该进气系统进行优化,从而在进气系统开发初期就对潜在的进气噪声问题进行管控。     

基于相位推导对尾端进气歧管的研究

发动机进气歧管作为进气系统的重要组成部分,其结构设计对进气系统的声品质具有重要的影响。在推导各支管相位角对进气歧管总管处声压阶次组成影响的基础上,以某工程试验车为研究对象,用GEM-3D软件建立进气歧管模型,并与在GT-POWER中建立的发动机模型相耦合,构建完整的发动机进气系统模型,在仿真与试验结果相吻合的基础上,根据理论推导,优化进气歧管。结果表明,通过调节各支管之间的相位差角,能增强发动机点火阶次的声压和降低半阶次声压,达到改善进系统声品质的效果。     

进气口噪声的测试方法研究

随着人们生活水平的日益提高,人们对汽车的舒适性要求越来越高。汽车的噪声是影响舒适性的关键因素之一,因此如何改善汽车噪声为当前汽车技术研究的重点方向之一。气噪声是车辆噪声的重要组成部分。本文基于某车辆在原车标准状态下,在整车半消试验室中,三档全加速（3G＿WOT）工况下测得的进气口噪声,通过GT-Power软件建立进气系统和发动机耦合的声学仿真模型,通过对比其仿真值与试验测试值,得出该测试方法测得的进气口噪声包含发动机背景噪声的结论。在节气门处接一段1.1m的白管,以此来将进气系统引出,并对车辆进行隔音处理,将测得的进气口噪声与模型仿真值进行对比,发现其结果基本一致。由此得出在节气门处接一段1.1m的白管来将进气系统引出的进气口噪声测试方法能更好地反应真实进气口噪声的结论。     

发动机进气系统声学元件设计方法研究

利用GT-Power软件建立了某发动机模型,进行了进气系统插入损失的分析,并找到了插入损失的3个最大值.结合插入损失的计算结果,利用所开发的进气系统声学元件中心频率设计专家系统.充分考虑各声学元件传递损失影响参数,依次进行了谐振腔、空滤器和四分之一波长管的设计.对发动机进气口噪声的计算机模拟仿真结果表明,本文提出的进气系统声学元件设计方法具有工程实用价值.     

AMESim仿真软件在燃料电池系统开发中的应用

利用AMESim软件建立了质子交换膜燃料电池发动机一维仿真模型,包括电堆、空气系统、氢气系统和冷却系统。从空压机选型、电堆运行条件匹配、冷启动和整车经济性四个方面介绍了AMESim仿真软件的应用。仿真结果表明,电堆运行条件对系统零部件选型尤其是空压机影响较大,适当降低进气计量比和进气压力可降低部件功率消耗,提升系统整体效率,PTC水加热器可以大幅缩短燃料电池发动机冷启动时间,减小系统怠速功率可提升整车经济性。应用AMESim软件进行仿真分析对于燃料电池发动机设计开发具体一定的指导意义。     

基于六西格玛方法的喷雾仿真控制参数优化

文章利用STAR-CD软件数值模拟汽油喷雾的发展过程,采用六西格玛设计(DFSS)思想,根据定容弹试验结果,对STAR-CD软件内部的所有喷雾仿真模型进行了分析和优选,并优化了模型的各个控制参数,设计了符合六西格玛设计流程的科学系统的标定喷油器的方法。     

并联式混合动力发动机扭矩管理模型仿真与试验研究

建立了基于扭矩的汽油机仿真模型,该模型可用于并联式混合动力电动汽车的控制策略的开发与仿真研究。在Matlab/Simulink中对基于扭矩控制的发动机模型进行了仿真,表明以扭矩为控制变量来确定进气充量、喷油量和点火正时的控制策略是有效的且适用于整车控制。另外,通过将扭矩估计模型的仿真结果与试验结果对比,验证了模型的准确性。最后介绍了发动机的基本标定试验。     

JK90S可调喷嘴涡轮配机特性的研究

以JK90S可调喷嘴涡轮与WD615.50型柴油机配机试验数据为基础,对采用GT-POWER建立的配机仿真模型进行了校验,使仿真的发动机参数和涡轮的进出口参数与试验值误差小于5%。采用校正后的GT-POWER配机仿真模型,对经过调节喷油量后的WD615.50型柴油机与JK90S增压器的配机运行工况进行仿真计算,确定了可调喷嘴涡轮随发动机工况变化时的最优开度脉谱图。     

氢燃料发动机三维数值模拟研究

通过CFD软件STAR-CD建立了缸外预混合氢燃料发动机三维模拟仿真模型。对比氢燃料发动机与汽油发动机的性能发现,氢燃料发动机具有易点燃、火焰传播速度快、峰值压力及峰值温度高等特点。但氢气密度低,与空气形成的混合气单位体积的热值低,导致采用缸外预混合方式的氢燃料发动机比汽油机功率低15%左右。研究了过量空气系数和点火提前角对氢燃料发动机性能及NOx排放的影响,为提高氢燃料发动机的动力性能和排放性能提供依据。     

Numerical investigation of turbolag reduction in HD CNG engines by means of exhaust valve variable actuation and spark timing control

Turbocharging port-injected Natural Gas (NG) engines allows them to recover gaseous-fuel related power gap with respect to gasoline engines. However, turbolag reduction is necessary to achieve high performance during engine transient operations and to improve vehicle fun-to-drive characteristics. Significant support for the study of turbocharged Compressed Natural Gas (CNG) engines and guidelines for the turbo-matching process can be provided by 1-D numerical simulation tools. However, 1-D models are predictive only when a careful tuning procedure is set-up and carried out on the basis of the experimental data. In this paper, a 1-D model of a Heavy-Duty (HD) turbocharged CNG engine was set up in the GT-POWER (Gamma Technologies Inc., Westmont, IL, US) environment to simulate transient operations and to evaluate the turbolag. An extensive experimental activity was carried out to provide experimental data for model tuning. The model buildup and tuning processes are described in detail with specific reference to the turbocharger model, whose correct calibration is a key factor in accounting for the effects of turbine flow pulsations. The second part of the paper focuses on the evaluation of different strategies for turbolag reduction, namely, exhaust valve variable actuation and spark timing control. Such strategies were aimed at increasing the engine exhaust-gas power transferred to the turbine, thus reducing the time required to accelerate the turbocharger group. The effects of these strategies were examined for tip-in maneuvers at a fixed engine speed. Depending on the engine speed and the applied turbolag reduction strategy, turbolag reductions from 70% to 10% were achieved.     

车用电控柴油机喷油器匹配仿真分析研究

本文介绍了车用电控柴油机喷油器匹配仿真分析研究过程。研究结果表明:GT-POWER软件可用于车用电控柴油机喷油器匹配仿真分析研究;所建立的仿真模型能准确模拟车用电控柴油机实际运行工况;确定了C型喷油器为本次仿真计算的最优匹配选择。     

燃油喷射参数对高压共轨柴油机性能的影响

运用GT—POWER软件建立了某高压共轨直喷柴油机的整机模型,并将计算值与试验值进行了比较,以确保模型具有足够的精度和可靠性;仿真分析了喷油压力、主喷提前角、预喷油量以及主预间隔对发动机性能的影响。仿真结果显示：增大喷油压力有助于提高发动机动力性和经济性并降低Soot排放;不同工况点需要选取不同的主喷提前角;增大预喷油量有助于降低NO。排放,但预喷油量不宜过大;主预间隔对Soot排放有较大影响。     

Pressure model based coordinated control of VGT and dual-loop EGR in a diesel engine air-path system

This paper describes a pressure-model-based coordinated control method of a variable geometry turbine (VGT) and dual-loop exhaust gas recirculation (EGR) in a diesel engine air-path system. Conventionally, air fraction or burnt gas fraction states are controlled for the control of dual-loop EGR systems, but fraction control is not practical since sensors for fractions are not available on production engines. In fact, there is still great controversy over how best to select control outputs for dual-loop EGR systems. In this paper, pressure and mass flow states are chosen as control outputs without fraction states considering the availability and reliability of sensors. A coordinated controller based on the simple control-oriented model is designed with practical aspects, which is applicable for simultaneous operations of high pressure (HP) EGR, low pressure (LP) EGR, and VGT. In addition, the controller adopts the method of input-output linearization using back-stepping to solve the chronic problems of conventional pressure-based controllers such as coupling effects between operations of HP EGR, and VGT. The control performance is verified by simulation based on the proven GT-POWER model of a heavy-duty 6000cc diesel engine air-path.     

基于GT-Power的天然气发动机动力性能恢复研究

利用GT-Power软件建立了4缸火花点火天然气发动机的一维仿真模型,并与试验结果进行了对比,仿真与试验结果一致性较好,证明了模型的准确性。在此基础上为天然气发动机匹配了涡轮增压及中冷系统,计算结果显示,增压后天然气发动机的动力性能明显提高,最大功率和扭矩较原汽油机分别提高了23%和9%,中低转速的有效燃气消耗率明显下降。进行了点火提前角的优化计算,得出了节气门全开条件下的MBT角—转速—空燃比三维MAP图。     

Application of a thermodynamic model with a complex chemistry to a cycle resolved knock prediction on a spark ignition optical engine

A combination of experimental and numerical methodologies is proposed for the investigation of knocking in spark ignition engines to aid in better understanding the physical and chemical processes that occur and to exploit the capabilities of a developed computational tool. The latter consists of a thermo-fluid dynamics model, which is part of an advanced 1-D fluid dynamics code for the simulation of the entire engine, and a complex chemistry model, which can be embedded into the thermo-fluid dynamics model using the same integration algorithm for the conservation equations and the reacting species. Their mutual interaction in the energy balance will be considered. The experimental activity was carried out in the combustion chamber of an optically accessible, single-cylinder P.F.I. engine equipped with a commercial head. The experimental data consisted of optical measurements correlated to the combustion and auto-ignition processes within the cylinder. The optical measurements were based on 2-D digital imaging, UV visible natural emission spectroscopy and the chemiluminescence of radical species (OH and HCO). The engine parameters, the pressure signals of the related data and optical acquisition are compared on an individual cycle basis in the simulation by running the engine at a constant speed and varying the spark advance from normal combustion to heavy knock conditions.     

汽油机活塞组一气缸套整体耦合传热模型及应用

采用直接耦合的有限元分析方法对一汽油机的活塞组一气缸套系统的瞬态传热过程进行了研究。通过将润滑油膜假设为一维热阻，建立了活塞组气缸套整体耦合系统的三维传热模型，应用所开发的三维流体动压润滑分析程序对活塞环组沿周向瞬时变化的油膜厚度进行了计算与分析。以LJ377MV汽油机活塞组一气缸套零部件为对象进行了应用研究，获得了更为清晰的多部件间的相互传热关系。     

汽油机活塞组—气缸套整体耦合传热模型及应用

采用直接耦合的有限元分析方法对一汽油机的活塞组—气缸套系统的瞬态传热过程进行了研究。通过将润滑油膜假设为一维热阻,建立了活塞组—气缸套整体耦合系统的三维传热模型,应用所开发的三维流体动压润滑分析程序对活塞环组沿周向瞬时变化的油膜厚度进行了计算与分析。以LJ377MV汽油机活塞组—气缸套零部件为对象进行了应用研究,获得了更为清晰的多部件间的相互传热关系。