密封对汽车冷却模块性能影响的数值分析

为优化汽车前端设计,提高发动机舱散热性能,针对某乘用车发动机舱冷却性能提出冷却模块空气流量、格栅进气利用率和散热器实际散热量等3个评价参数,通过CFD软件对4种汽车前端进气冷却模块密封方案进行三维仿真计算,研究冷凝器、散热器与风扇罩之间的不同密封情况对3个评价参数的影响.研究结果表明,双密封方案是提高冷却模块性能的最佳方案.     

装甲车辆柴油机冷却系统控制策略研究

建立了具有高低温双循环的装甲车辆冷却系统模型;在分析装甲车辆各部件冷却散热需求的基础上,设计了基于预置MAP与模糊控制相结合的高低温双循环冷却系统冷却液温度控制策略;在Matlab/Simulink中建立了冷却系统与其控制系统的耦合模型,仿真验证了控制策略的有效性;在冷却系统试验台架上验证了控制策略的可行性;研究表明采用预置MAP与模糊控制相结合的控制策略能够保证高温循环柴油机冷却液出口处温度波动不超过±1 ℃,低温循环冷散热器冷却液出口处温度低于设定值。     

一种汽车加速度传感器冷却系统

本实用新型提供一种汽车加速度传感器冷却系统,用于汽车部件的振动测试,包括加速度传感器,用于降低加速度传感器温度的冷却垫块,冷却垫块设置在加速度传感器与待测物体之间,且设有用于容纳冷却液的容纳腔;冷却循环装置,包括泵体及散热器,泵体、冷却垫块、散热器通过管道连接形成冷却液循环回路。汽车加速度传感器冷却系统,保证加速度传感器的工作温度稳定,可适用于温度较高的待测物体的加速度测量。     

基于模糊PID算法的动力电池液体冷却策略

为防止动力电池组温度过高、温度均匀性差影响其性能和电动汽车运行安全,必须对其采取有效的冷却策略.本文提出了一种基于模糊PID算法的动力电池组直接式液体冷却策略.首先,根据Bernardi生热率模型和牛顿冷却定律,建立了电池内阻随温度变化、对流换热系数随冷却液流速变化的单体电池集中质量热模型.然后,利用冷却液单向流动的温度变化特性递推出电池组集中质量热模型,并对其准确性进行验证.考虑到电池组热模型的非线性和时变特性,设计了基于模糊PID算法的液体冷却策略.最后,将该冷却策略用于电池组冷却系统,仿真结果表明,与传统PID冷却策略相比,模糊PID冷却策略可以缩短系统调节时间、减小电池组温度不一致性、提高抵抗电流扰动的能力,具有更好的冷却效果.     

汽车冷却系统常见故障诊断与分析

冷却系统的主要功能是把受热零件吸收的部分热量及时散发出去,保证发动机在最适宜的温度范围内工作,冷却系统按照冷却方式的不同可分为水冷和风冷两种。本文主要是从实际经验入手,详细介绍关于汽车的冷却系统的常见故障并着重对冷却液温度高的常见故障进行分析。     

汽车水泵与发动机冷却液温度过高关系研究

汽车水泵是发动机冷却系统中十分重要的部件,水泵的作用是能够提高冷却液的压力,从而促使冷却液在发动机的冷却水道内不断的进行循环,通过这种方式带走发动机工作过程中产生的热量,进而保持发动机的正常工作温度。     

基于格子波尔兹曼方法的机舱散热耦合分析

为指导前保险杠格栅及开口设计,研究冷却系统在特定工况下的散热性能和流场分布,建立具有详细的发动机舱几何信息的整车模型,利用格子波尔兹曼方法模拟整车在数字风洞中的热性能,得到机舱内流场和温度场以及散热器出水温度.分析结果与实验数据一致性很好,因此格子波尔兹曼方法很适合解决具有复杂几何结构的机舱散热问题.基于对标模型,针对前保险杠格栅的开口和格栅形式提出改进优化建议.经过多轮优化,散热器的散热能力提升6.94%.     

风扇矩阵对冷却模块空气侧流场的影响

基于传统乘用车的单风扇系统,提出5种风扇矩阵形式,利用数值模拟技术分析不同矩阵形式对冷却模块空气侧流场的影响,结果表明：随着风扇数目的增加,冷却模块表面的速度均匀度皆表现出先减小后增大的变化趋势;N=4的风扇矩阵的速度分布均匀性最差,对应通过散热器的空气流量亦最小; N=15的风扇矩阵能够显著提升通过散热器的空气流量,相比原单风扇系统,空气流量提升15.6%。因此,在不降低散热器空气侧换热能力的前提下,采用该风扇矩阵形式能够使冷却系统的能耗降低,提高整车燃油经济性。采用风扇矩阵形式能够减少冷凝器前端的热回流区域,从而降低冷凝器迎风面的平均温度。     

基于遗传算法的层流冷却系统优化控制策略

为进一步提高层流冷却系统的控制精度, 不仅要满足对卷取温度的要求, 还要满足控制冷却对冷却速率的要求. 本文以热连轧层流冷却系统的粗调区为研究对象. 综合考虑层流冷却控制系统的两个控制目标: 目标卷取温度与目标冷却速率, 直接将粗调区集管的开闭模式作为染色体的编码, 应用遗传算法搜索粗调区集管开闭的最佳模式. 最后对整个冷却控制系统进行了仿真, 结果表明采用该控制策略明显优于简单的前端密集冷却模式.     

基于KULI的发动机热管理瞬态模型的参数设置与仿真

以某重型柴油机为原型,利用KULI软件建立了发动机冷却系统模型,阐述了模型中发动机参数的设置原理,进行了瞬态工况下冷却液温度以及润滑油温度变化的仿真。结果说明：其仿真结果与实验数值吻合较好,模型精度可靠,模型中发动机的参数设置原理为发动机热管理瞬态模型的设置提供了一种方法,使用该方法可用来设置不同类型的发动机,为发动机热管理系统的仿真计算提供较为准确的放热边界条件,并进一步用来仿真完整的发动机热管理系统。     

汽车下护板对发动机舱散热性能的影响

为提高汽车发动机舱的散热性能,通过计算流体力学数值仿真研究汽车下护板对整车散热性能的影响。研究表明：在高速工况下,增加下护板后格栅和冷却模块进气量增加;在高负荷工况下,下护板可改善发动机舱的空气温度分布形态。下护板开口可增加冷却模块进气量,不开口时舱内温度较低,所以在整车设计时应综合考虑散热量和热害。下护板能明显减少风阻,但开口会减弱其效果,因此设计时应多方面考虑。     

Advanced automotive thermal management – Nonlinear radiator fan matrix control

Advanced automotive cooling systems for gasoline and diesel engines can improve the powertrain performance. The replacement of the mechanical driven coolant pump and radiator fans with computer controlled servo-motor actuators, and update of the wax-based thermostat valve with a 3-way variable position smart valve, allow the coolant flow rate and proportion directed through the radiator to be carefully adjusted. A smart thermal management system approach can regulate the forced convection heat transfer process to match the engine׳s cooling needs. This paper presents a Lyapunov based nonlinear control strategy to solely operate the radiator fan matrix for transient engine temperature tracking. A reduced order mathematical model serves as the basis for the closed-loop feedback system. An adaptive backstepping method was implemented to derive the control law. An experimental test bench with multiple radiator fans, heat exchanger, wind tunnel, coolant pump, three way valve, and engine thermal load has been fabricated. Representative numerical and experimental tests demonstrate that the advanced control strategy can regulate the engine temperature tracking error within 0.12 °C and compensate the unknown heat load. The nonlinear controller provided superior performance in terms of power consumption and temperature tracking as evident by the reduced magnitude when compared to a classical PI with lookup table based controller and a bang bang controller.     

发动机冷却系统的建模与仿真

该文在基于MATLAB/SIMULINK的环境中建立了某重型汽车柴油发动机冷却系统模型。该系统主要由发动机、节温器、散热器、水泵以及空气冷却系统组成。模型着重考虑了节温器的迟滞和热惯性等非线性特点，并建立了风扇的风速控制逻辑。在不同运行状况下仿真结果与相应的发动机实测数据基本一致，表明所建立的模型具有较好的温度预测能力。     

Hydraulic actuated automotive cooling systems—Nonlinear control and test

The replacement of traditional automotive mechanical cooling system components with computer controlled servo-motor driven actuators can improve temperature tracking and reduce parasitic losses. The integration of hydraulic actuators in the engine cooling circuit offers greater power density in a smaller package space when compared with electric actuators. In this paper, a comprehensive nonlinear backstepping robust control technique is developed to regulate the engine coolant temperature by controlling a hydraulic coolant pump and radiator fan. An experimental test bench has been assembled to investigate the hydraulic automotive thermal system performance. Representative numerical and experimental results are presented and discussed. Overall, the proposed controller was successful in tracking prescribed engine temperature profiles while harmoniously regulating the power consumption of the coolant pump and radiator fan.     

电动汽车轮毂电机散热规律

采用计算流体力学方法对电动汽车轮毂电机的散热规律进行数值仿真计算,得到整车流场下各电机的表面温度、表面传热系数,各车轮的空气质量流等参数的分布及变化规律。结果表明：前轮电机受前端散热模块影响较大;右前轮电机外壳温度高于左前轮电机和后轮电机;前轮电机表面传热系数明显大于后轮。随着车速的增加,产生较多的冷却气体,电机表面散热情况有所好转。     

Assessment of engine thermal management through advanced system engineering modeling

A physically based approach to model vehicle dynamics, transient engine performance and engine thermal management system is presented. This approach enables modeling dynamic processes in the individual components and is the dynamic interaction of all relevant domains. The modeling framework is based on a common innovative solver, where all processes are solved using tailored numerical techniques suited to account for characteristic time scales of individual domains. This approach enables achieving very short computational times of the overall model. The paper focuses on the integration of cooling and lubrication models into the framework of a vehicle dynamics simulation including transient engine performance demonstrated on a modern passenger car featuring split cooling functionality. A validated model with a mechanically driven coolant pump provides the base for analyzing the impact of introducing an electrically driven coolant pump. Analyses are performed for two drive cycles featuring significantly different velocity profiles to reveal their influences on the operational principles of the powertrain components and their interaction. The results show for both drive cycles fuel saving due to the application of the electric water pump is relatively small and amounts between 0.75% and 1.1%. However, it is important to address that application of the electric coolant pump results in higher turbine outlet temperatures and thus in faster catalyst heat-up. Detailed analyses of the interaction between vehicle dynamics, transient engine performance and engine thermal management system provide insight into the underlying mechanisms. This is made possible by the application of physically based system level model.     

不同前车车型对后车前端进气的影响

针对尾随行驶过程中前车对后车发动机舱冷却性能产生影响的问题,以轿车、皮卡车、面包车和城市公交客车作为前车车型,以轿车作为后车车型,分析不同车距下后车发动机舱进气质量流量比以及冷凝器入口的速度分布和流场.结果表明,当前车为轿车时对后车前端进气影响较小;当前车为皮卡车时后车前端进气随着车距的增加会先减少后增多,在车距为1倍后车车长时减少约7%;当前车为面包车或城市公交客车时对后车发动机舱的进气影响的变化规律一致,当车距为0.2倍后车车长时减少约13%.