车用发动机曲轴箱通风系统构成及常见故障分析

随着国家排放法规要求越来越严格,曲轴箱通风系统对整车排放的影响越来越大。本文介绍了车用发动机曲轴箱通风系统的构成及功能,构成包括通风腔、油气分离系统、曲轴箱压力控制系统、回油腔及呼吸管五部分;同时介绍了曲轴箱通风系统常见的故障模式并分析了失效原因,通常的故障模式包括:曲轴箱压力异常,烧机油,呼吸管结冰。     

现代发动机曲轴箱通风系统设计研究

近年来,随着排放法规的升级以及发动机可靠性能力提高,对曲轴箱通风系统设计提出巨大的挑战,主要表现为:1对于柴油机,为了降低曲轴箱排放物对环境的污染,闭式曲轴箱通风系统成为必然趋势;2对于汽油机,随着发动机强化程度提高(尤其是增压直喷发动机),同排量发动机漏气量急剧增加,但对曲轴箱通风系统机油携出量、曲轴箱压力都提出了更加严格的要求,从而造成系统设计难度大幅提升。本文基于一汽自主发动机开发过程中积累的大量经验,对曲轴箱通风系统设计过程中所采用的通风通道设计技术、油气分离及回油技术、曲轴箱压力控制技术及CAE模拟分析技术等进行了详细论述。     

浅谈柴油机的曲轴箱气体处理

随着国家环保升级至第六阶段,最新的环保文件GB17691-2018中对曲轴箱排放有明确规定,随着排放的一起升级的还有发动机的性能,而性能的提升往往会使发动机漏气量增加,曲轴箱气体里的机油含量增加,通常曲轴箱气体接入发动机进气口前需要进行处理。然后安装曲轴箱压力传感器监测曲轴箱压力,通过曲轴箱压力的变化来判断CV阀是否断开,达到OBD监测的目的。本文对曲轴箱强制通风系统主要零部件油气分离器、曲轴箱通气阀、加热器进行分析研究,对曲轴箱强制通风系统的设计有参考借鉴意义。     

增压发动机高寒试验故障分析与改进

某涡轮增压发动机在高寒试验过程中发生了发动机系统故障。通过对故障车辆进行了静态和动态检查,并且通过发动机台架试验和整车高寒试验,找到了导致车辆失效的根本原因为曲轴箱通风系统结冰和ECU故障所致。通过对曲轴箱通风系统当前设计的重新评估,将问题更加聚焦于解决曲轴箱通风管路1的结冰问题。通过多种方案的验证,找到了两个能有效解决曲轴箱通风管1结冰问题的方案,即增加电加热接头和将通风管1接至增压器压气机入口低端。     

浅析大众1.4T与皇冠2.0T发动机曲轴箱通风系统设计

为满足日益严格的汽车尾气排放要求和提高发动机的可靠性,曲轴箱通风系统设计的优劣已成为影响汽车发动机可靠性能的重要因素。近年来,各大汽车生产商多采用涡轮增压技术增强发动机动力性能,这使得活塞环处漏气量也大幅增加,同时,涡轮增压的发动机无法保证在任何工况下都像自然吸气发动机那样,利用曲轴箱和进气歧管内气体压力差的作用实现通风,因此,涡轮增压发动机对新的曲轴箱通风系统提出了更高的要求。本文结合大众1.4T和皇冠2.0T发动机搭载的新曲轴箱通风系统,分别对各自通风通道设计技术进行了详细论述。     

发动机冷启动试验曲轴箱压力高问题分析

为了满足自身曲轴箱的密封功能、以及维持活塞环的密封特性,发动机曲轴箱压力需要始终维持在微负压状态。曲轴箱压力是由曲轴箱强制通风系统进行调节控制的,特别是在极寒环境下,该系统极易结冰堵塞,导致压力升高。同时发动机在极寒工况下需要顺利启动点火,为了验证发动机是否能满足极寒工况点火特性,我司开发的发动机需要完成“发动机冷启动试验”。本文分析的是冷启动试验中,出现曲轴箱压力高后,排查曲轴箱通风系统解决问题的方法。     

基于STAR-CCM+的发动机曲轴箱通风系统CFD分析

为详细了解发动机曲轴箱通风系统内部的气体流动规律,采用STAR-CCM+模拟具有通风功能和无通风功能的两种曲轴箱通风系统它们各自内部的气体流动过程。计算结果表明,稳态情况下,曲轴箱通风系统内部除油气分离器外其它部分气体流速均较低;活塞漏气主要通过曲轴箱、前罩盖进入凸轮轴室,只有小部分气体通过回油道进入凸轮轴室;新鲜空气从通风管进入凸轮轴室后,大部分在凸轮轴室内流动,小部分通过回油道进入曲轴箱内,并与活塞漏气一起流向油气分离器;引入新鲜空气进入曲轴箱通风系统后,提高了曲轴箱通风系统整体的气体流动速度。     

产经要闻

曼·胡默尔开发出新型压力调节阀随着无限可调压力调节阀开发成功,曼·胡默尔工业集团提出了汽车曲轴箱通风系统压力调节的新概念。这种阀门的优势是可以使曲轴箱通风系统保持恒定的低压以更好地保护发动机。发动机的曲轴箱通风系统是一个与发动机吸入室相连的封闭系统。如果压力不可调,吸入室的负压将传递到曲轴箱的脱脂器。当负压超过80kPa,发动机垫圈将损坏,灰尘会进入发动机,加速发动机磨损。因此,调节压力十分重要。目前使用的一或两位阀不能提供可调节的压力,容易使相关的压力特性曲线出现尖峰。而该新型阀门结构简单、紧凑,具有很好…     

曲轴箱通风系统结冰试验分析与研究

曲轴箱通风系统的主要作用是将从曲轴箱抽出的气体导入发动机的进气系统重新燃烧。为了验证曲轴箱通风系统在极寒情况下是否有结冰风险,在冬季北方低温高湿环境下,在搭载某柴油机的某品牌汽车上进行通风系统结冰试验。试验过程中发现曲轴箱压力急剧升高试验被迫停止,拆解后发现呼吸器出气管靠压气机端结冰堵塞。为解决这一问题,在呼吸器出气管上增加保温套,提高窜气进入发动机进气总管时的温度,同时在呼吸器出气管与发动机进气总管连接处增加加热棒。     

浅谈汽油机尾气排放的控制

汽油发动机尾气排放控制主要分为机体内的控制和机体外的控制;关于机体外的控制,笔者从废弃再循环装置、二次空气供给系统、曲轴箱通风、燃油蒸发控制、三元转化催化装置等五个方面进行了阐述,并得出的结论是汽油发动机的尾气控制是综合控制,与多方因素有关.     

Development of a high performance railroad diesel engine oil for improved oil consumption control

High output railroad diesel engines today require high-performance crankcase lubricants, not only for extending drain intervals, but also for economising by lowering oil consumption. Although the importance of engine design in controlling oil consumption has been recognised for quite some time by the oil and railroad industries, another approach has been to reduce oil consumption by effective design of crankcase lubricants. This paper reports the development of a high-performance railroad diesel engine oil with superior detergency, dispersancy, oxidation and thermal stability characteristics vis-à-vis oils formulated with the latest generation packages. The same oil has also given reduced oil consumption in the Petter AV-1 performance engine test. Multigrading this formulation has resulted in further reduction in oil consumption.     

柴油机表面辐射噪声控制研究

为了降低发动机的表面辐射噪声,采用有限元分析方法对原柴油机下曲轴箱和通过添加加强筋方法改进后的下曲轴箱进行了模态计算分析,分别得到其固有频率和模态振型.声功率测算结果表明了方法的有效性.     

Interactions of Engine Oil Additives

Modern engine oil formulations usually contain many kinds of additives, such as detergent-dispersants, antioxidants, VI improvers, rust inhibitors, and friction modifiers. However, what these additives do in the crankcase is not yet fully understood. As a first step in clarifying the complex mechanisms of engine oil performance in the crankcase, the interaction of engine oil additives was studied on the basis of surface chemistry.

Metallic detergents form rigid micelles in oil, whereas ashless dispersants associate moderately and form small micelles in oil. No interaction was found between metallic detergents and zinc dithio-phosphate (ZDP), but there were strong interactions between ashless dispersants and metallic detergents and between ashless dispersants and ZDP. The adsorption onto an iron surface, the solubilization of sludge, and oxidation inhibition by engine oil additives are strongly influenced by the state of solution of these mixed systems.     

Accumulation of lead in ester-based engine oils

Synthetic esters are widely used as base-oil components in top-tier crankcase lubricant formulations. In combination with synthetic hydrocarbons, an ester content of between 10 and 50 wt.% is common. Only a few engine oils with an ester content above 85 wt.% have been introduced on to the market as yet. The use of such engine oils is advantageous, especially in environmentally sensitive areas, in terms of volatility, particle emissions, and biodegradability. Some older types of heavy-duty diesel engine continue to be run in vehicles and in machinery in the construction industry, and in such engines a higher lead content has been detected when ester-based engine oils have been used. It has been found that lead is extracted from the bearings and accumulates ultimately in the engine oil during operation. Consequently, the development of a suitable inhibitor system has been initiated to improve engine and bearing protection. To determine the effectiveness of the new inhibitors, a suitable test method had to be found. Using a test method based on the Petter WI (CEC L-02-A-78) test engine, the present paper summarises the results of tests on an inhibitor system to prevent lead extraction from bearings The metal contents reported in this paper were determined by ion conductive plasma atomic emission spectrometry.     

LJ465Q-1A曲轴箱的铸造工艺设计

介绍在采用湿型砂造型和覆膜砂制芯的条件下，如何合理进行LJ465Q—1A发动机曲轴箱铸造工艺的设计．有效降低铸件废品率的经验。     

利用气冲造型线生产LJ462Q-1曲轴箱的实践

总结利用潮砂模气冲造型线生产 LJ4 62 Q- 1型发动机曲轴箱的工艺实践 ,简述了气冲造型的工艺特性及其主要工艺参数的控制方法。     

发动机通风冷却系统的影响因素分析

整理了风斗进入短舱的冷气流量的变化规律,对发动机通风冷却系统各影响因素进行分析,分析了发动机状态、飞行状态（高度、马赫数）对飞机短舱内温度变化的影响规律。结果表明,发动机状态是影响发动机通风冷却系统的主要因素,飞行状态对涡喷和涡扇发动机通风冷却系统的影响规律不同。     

Oil soluble polyethers in automotive crankcase lubricants

The evaluation of oil soluble polyethers (OSPs) in fully and semi-synthetic automotive crankcase lubricants is described. Parameters including viscosity, additive compatibility, lubricity/wear performance, oxidative stability, and piston cleanliness are assessed. It is possible to formulate OSP-containing lubricants with lower VI improver treatment level, superior viscometric properties, and Noack volatilities to comparable lubricants without OSPs. Data from engine tests and field trials show that semi- and fully synthetic lubricants containing OSP possess all the performance advantages of ester-containing lubricants, with additional benefits in terms of engine and inlet system cleanliness. The results indicate that OSPs have excellent potential as synthetic lubricant base fluids.     

Effect of palm oil methyl ester and its emulsions on lubricant degradation and engine component wear

This paper presents the results of experimental work carried out to evaluate the effect of palm oil methyl ester also known as palm oil diesel (POD) and its emulsions, as alternative fuels, on unmodified indirect‐injection diesel engine wear and lubricant oil deterioration compared with ordinary diesel (OD). A constant 2500 rpm engine setting at half throttle was maintained throughout the wear debris and lubricant oil analysis period for 20 h for each fuel system. Samples of lubricant oil were collected through a one‐way valve connected to the crankcase sump at intervals of 4 h. The first sample was collected immediately after the engine had warmed up. The same lubricating oil, a conventional SAE 30, was used for all experiments. A multi‐element oil analyser was used to measure metal wear debris and lubricating oil additive depletion for the used lubricating oil. An ISL automatic houillon viscometer (ASTM D 445) and potentiometric titration (ASTM D 2896) were used to measure the viscosity and total base number, respectively. The lubricant oil analysis results for POD, OD, and their emulsions containing 10% water by volume were compared. Very promising results were obtained. The accumulation of metal wear debris in crankcase oil samples was lower with POD and its emulsion compared with the OD fuel. The addition of 10% water (by volume) to POD showed a promising tendency for wear resistance.