柴油机水温偏高的处理

柴油机闭式循环冷却系统是将柴油机出来的高温冷却液,通过水散热器靠风扇强力鼓风来冷却,冷却后的水再去冷却柴油机。冷却系统出现故障后,水温会升高,这种情况约占80％。依据高温症状,按照由简单到复杂的原则,应先检查冷却系统,再检查柴油机本身。     

YL70-265型压裂车柴油机水温过高原因分析及措施改进

详细分析了YL70—265型压裂车柴油机水温过高的原因,提出了对柴油机冷却系统进行改进的方案、措施,解决了YL70—265型压裂车柴油机水温过高、冷却液沸腾的故障,保障了柴油机的正常运转,延长了柴油机的使用寿命。     

汽车冷却系统的温度控制试验研究

对传统冷却系统进行改造设计,结合冷却风扇的电动控制形成了智能化控制的冷却系统,从而,实现了风扇转速随发动机工况变化进行自动调节,真正实现了冷却水温的精确控制,保证了冷却水温始终保持在最佳范围内,并提高了发动机工作的可靠性。     

柴油机风扇系统仿真分析与优化

对某柴油机风扇系统进行了模态和强度仿真计算,并根据计算结果中的不合格项对这一风扇系统进行了优化.通过仿真分析与优化,保证了柴油机风扇系统零部件设计的可行性,并且可以节约研发时间和成本.     

柴油机空气动力噪声分析及控制方法研究

柴油机因为具有经济性和排放性等优点而受到广泛应用,但同时它也会产生很大的噪声。讨论了柴油机的噪声危害,按辐射方式对柴油机噪声进行了分类,并重点分析了空气动力噪声,分别从进气、排气和风扇等方面介绍了柴油机空气动力噪声的产生机理和控制方法。研究表明,进气噪声和排气噪声的控制大多采用添加消声器的方法,风扇噪声的控制大多从风扇的结构参数和布置形式着手考虑。介绍了CFD建模及仿真分析噪声的思路方法,为后续优化设计打下基础。但在降低噪声的同时,必须保证风扇的其他性能参数达到所需要求。     

装载机液压系统故障3例

(1)水温过高1台沃尔沃180C型装载机工作10～20min,水温即升至95℃以上。首先,检查水散热器表面清洁,水温传感器和水温表灵敏准确,节温器能够正常启闭,发动机运转平稳有力,但冷却风扇转速稍慢。其次,用压力表检测冷却风扇驱动泵(P3泵)输出压力偏低。调整P3泵压力调节器调整螺栓,压力没有变化。再次,将压力调节器拆解、清洗、检查,未发现异常。对p3泵进行拆解、清洗、检查,也未发现异常。最后,将风扇马达拆解、清洗、检     

自卸车柴油机水温高故障诊断

正1辆CQ3253TMG324型红岩自卸车,其所配装柴油机型号为WD615.50。该车在平路行驶时柴油机水温正常,一旦爬坡或柴油机转速提高,水温会突然升高;而下坡时,水温下降很快,现针对上述故障进行排查。     

自卸车柴油钔水溻高故障诊断

1辆CQ3253TMG324型红岩自卸车,其所配装柴油机型号为WD615．50。该车在平路行驶时柴油机水温正常,一旦爬坡或柴油机转速提高,水温会突然升高;而下坡时,水温下降很快,现针对上述故障进行排禽。     

液压挖掘机发动机冷却水温度过高的原因

我单位有两台美国 CAT 325BL液压挖掘机,使用中发现发动机常常水温过高,我们分析主要有3个原因。1．冷却系统进风量不足造成散热不良,导致水温过高在设计上,CAT 325BL液压挖掘机是采取冷却风扇对发动机散热器(即水箱)进行强制冷却的,冷却风扇     

VOLVOL220E装载机水温报警故障分析

发动机在正常工作状态下,发动机的冷却液温度一般维持在90℃左右,若发动机冷却液温度高于正常值,那么水温传感器就会提示报警,应立即停机查找原因,避免发动机过热损坏。本文结合VOLVOL220E型装载机水温高报警故障,分析常见水温报警故障原因,即机械故障、电气故障、风扇液压系统故障,着重阐述风扇液压系统工作原理,以及比例电磁阀MA202控制液压泵输出流量的工作机制,通过分析故障现象确定MA202损坏是导致风扇转速偏低,水温升高的主因,更换电磁阀,故障得到解决。     

Psychoacoustic study on contribution of fan noise to engine noise

There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure,and a lot of research achievements have been obtained.However,researches on the effect of fan noise to engine noise quality are lacking.The influences of the effects of fan structure optimization on the engine noise quality are unclear.Thus,there will be a decline in fan noise level,but the deterioration of engine noise quality.Aiming at the above problems,in consideration of fan structure design and engine noise quality,an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed.The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method.The experiment results are regarded as analysis samples.The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans.Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased,and the increase is 13.53% on average,which indicate the improvement of the engine noise quality.In order to verify the psychoacoustical analysis,the subjective assessment is carried out.The test result shows the noise quality of engine installed10-blade fan in medium diameter is most superior.1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality.It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased,the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise.The psychoacoustic study is applied in the contribution of fan noise to engine noise,and the idea of engine sound quality improvement through the structure optimization is proposed.     

某海洋平台废气涡轮增压中冷柴油机提高性能探究

废气涡轮增压中冷柴油机广泛应用于海上油气开发,在柴油机运行过程中,增压后空气温度下降可以提高进气空气密度,进而提高柴油机功率以及效率。通过现场运行分析发现,随着柴油机功率提高和空冷器换热效率下降,增压空气温度上升,而柴油机低温水出口温度设定为50℃不变,导致了柴油机性能降低。本研究通过理论分析、实验等方式对该柴油机进气温度可变性进行分析研究,寻求最佳进气温度以提高主机燃油效率、降低排气温度及污染物排放。     

Feasibility and performance study of turpentine fueled DI diesel engine operated under HCCI combustion mode

In the present investigation a volatile fraction of Pinus resin called Turpentine has been experimented in a direct injection diesel engine under HCCI combustion mode. The engine chosen to experiment is a single cylinder DI diesel engine and modified in such a way to ignite Turpentine in a diesel engine under HCCI mode. As the Turpentine has a higher self ignition temperature the ignition of Turpentine in regular diesel engines with auto-ignition is not possible. Hence, suitable modification is made in the engine to ignite Turpentine in a diesel engine like diesel fuel. The modified engine has ECM controlled fuel spray and an air preheater in the suction side of the engine. The combined effort of adiabatic compression and supply of preheated air ignites turpentine by auto-ignition and its timing of ignition is precisely controlled by changing intake air temperature. This investigation revealed that the engine operated with turpentine performed well with little loss of brake thermal efficiency. And, emitted comparatively lower emissions such as NO_x and smoke and proved that the turpentine is a best suited fuel for HCCI operation.     

柴油机中冷器的结构与设计研究

在内燃机车当中,柴油机中冷器的功能是使柴油机在运行时增压状态下的空气温度得以降低,同时使空气的密度增加,进而增加柴油机的循环进气量。在热负荷增加的情况下,中冷器可以有效提高柴油机的运行功率,实现资源的合理利用,减少有害气体的排放量。通过对柴油机中冷器的优化设计,可以使设备的优势得到更为充分地发挥,促进柴油机性能的优化与提升。     

柴油车燃油预加热系统设计方案

本设计方案主要是为了解决当车辆所行驶的外界温度低于车辆所加注的柴油能够使用的最低温度,造成柴油流动性下降从而引起的发动机供油不畅甚至熄火的问题。通过利用发动机排气余热给油管内的柴油预加热,使之能够给发动机提供满足其正常工作需要的燃油的目的。并能够适当降低柴油牌号(实现在使用-10号柴油的地区用0号代替)从而进一步提高车辆的使用经济性。     

中速柴油机冷却系统恒温控制设计与研究

针对柴油机不同的工况对冷却水温度要求不同,原冷却系统不能随工况的变化自动调节温度,设计了柴油机智能冷却系统恒温控制系统。通过热平衡实验获得柴油机各工况最佳工作状态的冷却水温度和流量,利用单片机控制变频器水泵转速和电控三通旁通阀的开度对冷却水温度自动控制。实验结果表明:该系统可以随柴油机工况变化将冷却水温度恒定控制在最佳工作温度,达到了节油效果,最大节油率为5.4%,平均节油率为3.6%。     

柴油甲醇双燃料发动机动力性与经济性试验分析

介绍了柴油引燃甲醇双燃料燃烧对柴油机动力性和经济性的影响。在1台单缸、直喷、中冷柴油机上采用柴油引燃甲醇双燃料进行试验。结果显示甲醇柴油双燃料发动机在中高负荷及中高转速下运转可获得较好的燃油经济性。选择适当的引燃柴油量,双燃料发动机的动力性可以达到甚至超过原柴油的动力性。     

基于ART-并行BP神经网络的柴油机故障诊断研究

造成柴油机故障的因素十分复杂,既存在单一类的故障,也存在多故障并存的现象,而且还会出现新型故障,仅仅依靠单一神经网络技术的故障诊断已经很难满足对柴油机的有效诊断要求。本文在信息决策层融合的基础上,以自适应谐振理论ART和误差反向传播并行BP两种神经网络为基础,建立了用于柴油机故障诊断的新型神经网络模型,以对柴油机系统工作过程多种故障进行诊断识别。通过与单一神经网络诊断识别结果的分析和比较,验证了该神经网络诊断模型的可行性,它能够进行多传感器信息综合诊断,既能识别单故障和并发故障,又具有识别新型故障的能力,可有效地提高对柴油机故障诊断的准确性和可靠性。     

Specific engine performance and gaseous emissions characteristics of European test cycle and worldwide harmonized driving cycle for a heavy-duty diesel engine

This study compares the engine operating behavior and regulated gaseous emissions characteristics between the reference European cycles (ESC/ETC) and the worldwide harmonized driving cycles (WHSC/WHTC), which will be applied in the Euro VI heavy-duty diesel engine emissions regulations, for the diesel particulate filter (DPF) equipped Mercedes 12 L diesel engine. The speed and load distribution for two additional representative harmonized cycles which cover a more realistic operating range for a heavy duty engine were established to verify the engine performance over wide range of the cycle work, fuel consumption, and exhaust system temperature as well as engine coolant temperature for repeated validation tests. The WHTC, including an additional test with cold start and transient operation before the hot start, had a substantial influence on the THC, CO, NOx, and PM exhaust emissions levels because of the engine heat-up time and temperature rising characteristics of aftertreatment device. Moreover, the different engine operating conditions of the WHSC influenced on the specific engine performance and gaseous emissions behavior unlike those of the ESC. Finally, the statistical analysis results through repeated tests validated the stationary and transient cycles running at the fully warm-up condition, however, those of WHTC were closely dependent on the inclusion of cold start condition or aggressive acceleration gradient of engine speed and load trace.