喷嘴结构对船用低速柴油机燃烧的影响

刘辰朋，桂勇，刘腾，屠丹红

中船动力研究院有限公司, 上海200129

摘要：应用三维计算流体动力学软件对某船用低速柴油机的缸内燃烧进行研究，分析喷油器结构参数对缸内燃烧的影响。结果表明：喷油器喷嘴深入燃烧室内的长度较短时，缸内燃烧较差，导致缸盖过热；随着喷嘴伸入燃烧室内的长度增加，缸内燃烧情况得到改善，燃烧持续期逐渐缩短，NOx排放逐渐增加。随喷孔逆缸内涡流的径向角度增加，缸内燃烧情况逐步改善，燃烧室壁面传热减少；随喷孔倾斜角度增加，活塞表面受热增加。对新开发机型燃烧系统的研究发现：喷嘴的喷孔倾斜角度保持不变，将喷嘴长度增加10 mm，径向角度沿喷嘴轴线逆时针旋转10°或15°，缸内燃烧性能得到明显提升。

关键词：喷嘴长度；喷孔方向；径向角度；倾斜角度；燃烧持续期；NOx排放

China Shipbuilding Power Engineering Institute Co., Ltd., Shanghai 200129, China

Abstract:Three dimensional CFD software is used to study the incylinder combustion of one low speed marine diesel engine. The influence of different injector structure parameters for cylinder combustion is analyzed. The results show that when the length of the nozzle tip penetrating into combustion chamber is short, the combustion is poor, and the cylinder head is usually overheated. With the increase of nozzle tip length, the combustion duration is gradually shortened and the NOx emission is gradually increased. With the increase of the radial angle of the injector hole in the opposite direction against the swirl, heat transfer on the wall of the combustion chamber decreases. With the increase of the inclination angle of the injector hole, the heat transfer on the piston surface increases. For the nozzle designed for a new developed combustion system, if the length of the nozzle is increased by 10 mm, the inclination angle of the nozzle hole remains unchanged, and the radial angle rotates counterclockwise along the axis of the nozzle by 10° or 15°, the incylinder combustion performance will be improved obviously.

Keywords:nozzle tip length; injector hole direction; radial angle; inclination angle; combustion duration; NOx emission

柴油机SCR性能试验台测控系统开发

王荣旭1，盖永田2，梁鹏飞3，张强1，于泽庭1，纪少波1*

1.山东大学能源与动力工程学院，山东济南250061；

2.中国重型汽车集团有限公司汽车研究总院，山东济南250031；

3.中船重工第七一一研究所,上海201108

摘要：设计一种柴油机选择性催化还原（selective catalytic reduction，SCR）性能试验台测控系统，测控系统包括采集控制模块及上位机软件两部分，检测SCR系统稳定性并进行试验分析。基于MC9S12XEP100高性能单片机设计采集控制模块，测量催化器前、后排气温度，催化器前、后压差，尿素箱液位；获取催化器前、后NOx体积分数；实现继电器、尿素喷射电磁阀和尿素泵的运行控制。基于VC++开发上位机软件，实现尿素泵运行控制、尿素喷射量控制及加热控制和各传感器数据的实时显示。试验结果表明：基于该测控系统搭建的SCR测试试验台，信号采集传输以及各类执行器能够有效运行，测控系统工作稳定、有效。

Abstract:A measurement and control system for diesel engine selective catalytic reduction (SCR) performance testbed which includes acquisition control module and host computer software,is developed to detect the stability of SCR system and carry out experimental analysis. Based on MC9S12XEP100 high performance single chip microcomputer, the acquisition and control module is designed, which can measure the exhaust temperature before and after the catalytic converter, the pressure difference before and after the catalyst, and the liquid level signal of urea tank; obtain the NOx concentration (volume fraction) signal before and after the catalyst; realize the control of relay and urea injection solenoid valve and the operation control of urea pump. The host computer software is developed based on VC++, which can realize the operation control of urea pump, the control of urea injection quantity and the control of heating, the real-time display of sensor data. The results show that the SCR testbed based on the measurement and control system,the signal acquisition and transmission as well as all kinds of actuators can run effectively, which proves the feasibility and the effectiveness of the development of the measurement and control system .

Keywords:diesel engine; SCR;performance test;control system

多工况下排气特性对CRT后处理装置的影响规律

郑永祥1,2，钟静1,2，廖健雄1,2，李泽西1,2，胡杰1,2*

1.武汉理工大学现代汽车零部件技术湖北省重点实验室，湖北武汉430070；

2.武汉理工大学汽车零部件技术湖北省协同创新中心，湖北武汉430070

摘要：基于GTPower一维仿真软件，建立连续再生式捕集器（continuously regenerating trap, CRT）装置的仿真模型，通过台架试验验证模型的准确性。基于所建立的仿真模型，在稳态工况下研究排气组分、排气流量、排气温度对CRT装置不同测点温度和压差的影响；在瞬态工况下研究温度突变、排气流量变化、以及不同碳载量对后处理装置温度传递的影响。结果表明：稳态工况下，随着各排气组分浓度增加，CRT测点的压差基本没有影响，但中点和出口温度升高；排气流量增大导致压差线性增加；排气温度升高导致柴油氧化催化器入口和出口温差增大。在瞬态工况下，温度大于700 K时，催化型颗粒物捕集器（catalytic diesel particulate filter, CDPF）前后温差变为负值，CRT装置各轴向测点温度变化时间出现延迟；温度突变对温度变化和稳定时刻延迟时间没有影响；排气流量增加减少了温度变化时刻延迟时间、温度稳定时刻延迟时间和持续时间；CDPF碳载量增加增加了出口温度变化时刻延迟时间和持续时间。

关键词：柴油机；连续再生捕集器；排气特性；瞬态工况；延迟时间

Abstract:Based on GTPower onedimensional simulation software, a continuous regenerative trap CRT device model is established which is verified by bench test. The effect of exhaust component, exhaust flow rate and exhaust temperature on the temperature and the pressure drop for different measuring point of the CRT device are investigated under steadystate conditions. Meanwhile, the effect of temperature change, exhaust flow rate and carbon loading on temperature transfer are studied under transient conditions. The results show that with the increase of exhaust component concentration, the midpoint and outlet temperature increases at the same time, but the pressure drop is almost unchanged. The pressure drop increases linearly with the increase of exhaust flow rate, and the increase of exhaust temperature increases the absolute temperature difference inlet and outlet of DOC. When the temperature is over 700 K, the temperature difference before and after CDPF becomes abnormal, and the temperature change time of different axial measuring points of CRT device will delay. Temperature jump has no effect on time delay. The time delay decreases with the increase of exhaust flow and the higher carbon loading increases the time delay.

Keywords:diesel engine; continuous regeneration trap; exhaust characteristics; transient operation; time delay

快速预判整车PN排放的试验分析方法

姬忠锐1，杨文娟2，王镇1

1.潍柴动力股份有限公司，山东潍坊261061；2.盛瑞传动股份有限公司，山东潍坊262100

摘要：针对重型商用车国六排放标准中整车实际道路粒子数量（particle number，PN）的排放限值及测量方法难以适用于日常车辆的抽检和快速摸底的问题，借鉴大数据思想，研究PN排放低于限值、处于限值边界、严重超出限值3种情况下PN的瞬态排放水平及规律，并在瞬态排放水平与国六标准限值之间建立经验公式；提出模糊边界的整车排放试验分析方法和单位归一法。经验证，本文中提出的经验公式和方法，能够快速预判整车PN排放水平，提高抽检效率，可以为设计开发满足PN排放标准的整车、柴油机颗粒补集器故障模式分析、整车非标准循环的试验研究等提供必要参考和依据。

关键词：便携式排放测试系统；PN排放；模糊边界；整车运行工况；整车排放

Abstract:Aimed at the problem that the real road PN emission limits and measurement methods for emissions from diesel fuelled heavyduty vehicles (CHINA VI) is not suitable for the daily random inspection and quick survey of vehicles, based on the statistics of a large sample of data, the transient emission levels and rules of PN are studied of three situations in which PN emissions are below the limit, at the boundary of the limit and seriously beyond the limit. Further more,an empirical formula between the transient emission levels and CHINA VI standard limits is established, the “vehicle emission test analysis method with fuzzy boundaries” and “unit normalization method” are developed.It has been verified that the conclusions and methods in this paper are not only suitable for the rapid prediction of PN emission level, improve sampling efficiency,but also provide necessary reference and basis for the future design and development of PN emission and the failure mode analysis of DPF and the test research of nonstandard cycle.

Keywords:PEMS; PN emissions; fuzzy boundary; vehicle operating conditions; vehicle emissions

非道路国四阶段柴油机机内净化试验研究

赵联海1,2，史彦晓1,2，耿国芳1,2

1.内燃机可靠性国家重点实验室，山东潍坊261061;2.潍柴动力股份有限公司，山东潍坊261061

摘要：为降低柴油机NOx、烟度和颗粒物（particulate matter,PM）的排放，秉持设计、仿真、试验一体化的理念，基于PM生成机理，对采用废气再循环（exhaust gas recirculation,EGR）路线非道路国四阶段柴油机进行优化。在合理的试验设计基础上，结合实际路谱制定控制策略，围绕进气均匀性、预喷量、 喷油锥角等进行试验及仿真，提出减少进气管壁凹坑、使用厚度为1.0 mm的喷油器垫片、减小EGR阀开度闭环控制的前馈开度等优化措施，有效降低挖掘机尾气排放。

关键词：柴油机；仿真；高轨压；EGR

Abstract:In order to reduce the emissions of NOx, soot and PM of diesel engine, the engine of the nonroad China IV excavator is optimized by adopting EGR route based on the PM generation mechanism and adhering to the concept of integration of design, simulation and test. On the basis of design of experiments, combined with the actual road conditions, the spectrum control strategy system is formulated, and the test and simulation are carried out around the intake uniformity, preinjection amount and injection cone angle. The optimization measures such as reducing the intake pipe wall pit, using injector gasket with thickness of 1.0 mm, and reducing the feedforward opening of EGR valve closedloop control are proposed to effectively reduce the exhaust emission of excavator.

Keywords:diesel engine; simulation; high rail pressure; EGR

某瓦斯发电机组可调式文丘里混合器计算分析

余小松

山东新奥能源发展有限公司，山东济南250014

摘要：为解决某瓦斯发电机组可调式文丘里混合器燃气入口开度的标定问题，确保混合器能根据现场瓦斯参数匹配合理空燃比，减少机组现场调试时间和工作量，结合该机组理论燃烧体积空燃比及过量空气系数的要求，采用流体仿真软件ANSYS CFX对某瓦斯发电机组配套的可调节式文丘里混合器进行流场仿真计算，得出不同甲烷体积分数、不同压力的瓦斯在机组正常运行时所需的燃气入口开度。经现场实际验证，标定数据满足机组实际运行需求，可以为瓦斯发电机组现场调试提供数据参考，节省现场运行时的调试时间，节约调试成本。

关键词：可调式文丘里混合器；ANSYS CFX；气体流场；燃气入口开度

Abstract:In order to solve the calibration problem of the gas inlet opening value of the adjustable Venturi mixer for a gas generator set, ensure the reasonable airfuel ratio according to the field gas parameters, and reduce the time and workload of unit commissioning for the gas generator, combined with the theoretical combustion volume airfuel ratio and excess air coefficient requirements,used the fluid simulation software ANSYS CFX to simulate the flow field of an adjustable Venturi mixer for a gas generator set,the gas inlet opening map for the adjustable Venturi mixer under different concentration and pressure of gas are obtained. The actual application shows the calibration data meets the actual operation requirements of the gas generator set,it can provide reference data for gas generator set in scene adjusting, save time and cost when adjusting.

Keywords:adjustable Venturi mixer; ANSYS CFX;gas flow field;gas inlet opening value

空气压缩机气缸体热-机耦合分析改进

马辉，张创科，孙俊花，于巍

瑞立美联制动技术（廊坊）有限公司，河北廊坊065000

摘要：建立空气压缩机装配的三维有限元模型，根据温度场的热边界计算公式和试验数据，对空气压缩机的热边界条件参数进行修正，得到空气压缩机稳态工况下温度场的分布情况。采用多物理场耦合方法，计算气缸体在螺栓预紧力、温度和气体压力等工况下的变形情况。结果表明，缸盖螺栓预紧力和气体力对气缸体变形影响最大，在工作条件下，热负荷对气缸体变形影响较小。对气缸体结构进行改进，在45°、135°、225°和315°处各增加一条加强筋，使空气压缩机气缸体的变形平均减小了约45%。

关键词：空气压缩机；气缸体；热变形

Abstract:The finite element model of air compressor assembly is established. According to the test data of the temperature field, the thermal boundary parameters of the air compressor are corrected to obtain the distribution of the temperature field under steady state in the working process. The multi-field coupling method is used to calculate the deformation of the cylinder under the condition of bolt pretension, temperature and pressure. The results indicate that cylinder head bolt pretension and gas pressure has the greatest influence on the deformation of the cylinder. The cylinder block structure is improved by adding a reinforcingrib at 45°，135°，225°and 315°respectively, and the deformation of cylinder block is reduced by about 45%. The results show that the improvement is effective.

Keywords:air compressor; cylinder block; thermal deformation

DPF系统灰分含量预估可信性诊断方法

秦涛1,2，李国朋1,2，张雷波1,2，江楠1,2

1.内燃机可靠性国家重点实验室，山东潍坊261061；2. 潍柴动力股份有限公司，山东潍坊261061

摘要：对柴油颗粒过滤器（diesel particulate filter，DPF）系统灰分含量预估的可信性诊断进行研究，确保DPF主动再生时碳载量预估的准确性。在DPF再生后记录再生完成时刻的排气流量、DPF温度、DPF压差等相关特征参数，利用特征量反推DPF中的灰分含量。对比分析模型预估灰分含量与计算灰分含量，对模型预估灰分含量的可信性进行评估和修正，确保DPF主动再生时碳载量预估的准确性。仿真分析结果表明，预估灰分含量可用于DPF系统灰分含量预估可信性诊断。

关键词：DPF；灰分；诊断；可信性

Abstract:This paper introduces a credible diagnostic method for ash content estimation of DPF (diesel particulate filter) system, which is used to ensure the accuracy of carbon load estimation during DPF regeneration. The exhaust gas flow rate, DPF temperature and pressure difference are recorded when regeneration is finished. These parameters are used to estimate the ash component in the DPF. The estimated ash content of the model is compared with the calculated ash content, and the credibility of the model for ash content is evaluated. This model is used to ensure the accuracy of the carbon load estimation during active regeneration of the DPF. By simulation, the estimated ash content of the model can be used for credible diagnostic of ash content estimation of DPF.

Keywords:DPF; ash; diagnosis; credibility

铝活塞环槽表面Ni-SiC耐磨涂层的制备及性能试验研究

赵小峰1，2，刘国强1，2，王大江1，2，石小明1，2，段成林1，2,刘宗举1，2

1.滨州渤海活塞有限公司,山东滨州256602；2.山东省发动机活塞摩擦副重点实验室,山东滨州256602

摘要：为了提高活塞环槽的硬度和耐磨性能，采用共沉积技术在活塞一环槽部位制备NiSiC耐磨涂层。研究表明，当电流密度为5 A/dm2时，涂层生长速度最快且没有外观缺陷；电镀液温度为50~60 ℃时，涂层的内应力最稳定；电镀液的pH值为4~5时，制备的涂层质量最好；搅拌速度为250 r/min时，涂层中的共沉积颗粒的含量最高、颗粒分布最佳。分析涂层的硬度、摩擦磨损性能可知，制备的NiSiC涂层能够均匀地覆盖在基材表面，涂层最外层HV硬度可达700~800，耐磨性能是硬质阳极氧化铝涂层的2~3倍。对使用该涂层的活塞进行额定工况试验和对比试验，结果表明：涂层完好无脱落，磨损量符合要求。

关键词：NiSiC耐磨涂层；环槽；硬度；耐磨性

Abstract:In order to improve the hardness and wear resistance of piston ring groove, the NiSiC wearresistant coating is prepared on the piston ring groove by codeposition technology. The results show that the coating grows the fastest and has no appearance defects when the current density is 5 A/dm2,the internal stress of the coating is the most stable when the temperature of the transition fluid is 50~60 ℃,the coating quality is the best when the pH of electroplating solution is 4~5,when the stirring speed is 250 r/min, the content of codeposited particles reaches the maximum and the best particle distribution. Through the analysis of the hardness and friction and wear properties of the coating, it can be seen that the prepared NiSiC coating is evenly covered on the surface of the substrate, the HV hardness is 700~800 , and the wear resistance is 2~3 times of that of the same thickness hard anodized aluminum. The rated condition tests and comparative tests results show that the coating is in good condition without cracking and the wear amount meets the requirements.

Keywords: NiSiC wear resistant coating; ring groove; hardness; wear property

柴油与天然气对发动机活塞结构设计的影响

王奇峰1，2,马呈新1，2,曹江鹏1，2,刘云芳1，2,夏金宝1，2

1.滨州渤海活塞有限公司，山东滨州256602；2.山东省发动机活塞摩擦副重点实验室，山东滨州256602

摘要：分析柴油和天然气2种燃料的性能和燃用2种燃料的发动机及活塞结构的异同，对2种燃料发动机的活塞燃烧室、内冷油道、火力岸及环槽等结构进行设计，并利用有限元分析软件ANSYS计算不同燃料活塞的温度和热机耦合应力分布以及疲劳系数。1000 h耐久试验表明：2种燃料发动机的活塞整体状况良好，均顺利通过试验；相比柴油机活塞，天然气机活塞内冷油道部位的温度降低34.1 ℃，最大热机耦合应力降低7.6 MPa。

关键词：商用车；活塞结构；有限元分析；耐久试验

Abstract:The performance of diesel and natural gas, the similarities and differences of the two kinds of engine and pistons used for diesel and natural gas engine are analysed.The structures of piston including the piston combustion chamber, the cold oil duct, the fire shore and the ring groove are designed. Finite element analysis is also used to calculate the temperature, thermalmechanical coupling stress distribution and the piston fatigue coefficient. After 1000 h endurance test, the results show that the pistons of the two engines are in good condition and pass the test successfully. Compared with the piston of diesel engine, the temperature of the cold oil passage in the piston of natural gas engine is reduced by 34.1 ℃, and the maximum thermally coupled stress is reduced by 7.6 MPa.

Keywords:commercial vehicle;piston structure; finite element calculation; endurance test

气缸盖总装流水线的设计应用

张士越1，胡凤芹2

1.淄博淄柴新能源有限公司，山东淄博255000；2.淄柴动力有限公司，山东淄博255000

摘要：为提高气缸盖部件的装配质量，减少人工装配出现的偶然误差，提高生产效率，设计气缸盖总装流水线。优化气缸盖部件组装的工艺流程，对气缸盖部件组装线中的主要气动、液压、机械机构等进行设计及验证。实际应用表明：该流水线可以取代人工搬运敲击装配的传统模式，实现气缸盖组装工序的集中化，降低工人的劳动强度，保证产品装配的一致性，生产效率提高75%以上。

关键词：柴油机；气缸盖；装配线；研配

Abstract:In order to improve the assembly quality of cylinder head, reduce the accidental error of manual assembly, and improve the production efficiency, an assembly line of cylinder head was designed. By optimizing the process of cylinder head assembly , and the main pneumatic, hydraulic and mechanical devices of the cylinder head assembly line are designed and verified. The practical application shows that the assembly line replaces the traditional mode of manual handling and tapping assembly, which can realize the centralization of cylinder head assembly process, reduce the labor of workers, ensure the consistency of product assembly. The production efficiency can be improved by more than 75%.

Keywords:diesel engine;cylinder head;assembly line;research and assembly

气缸盖铸造工艺孔密封方案的研究与应用

田身军，李德银，项大伟，齐少虎，张镇，昂亮

奇瑞汽车股份有限公司 动力系统技术中心，安徽芜湖241009

摘要：为解决集成排气歧管缸盖铸造工艺孔密封问题，研究密封孔应用环境，对比钢球、拉涨式堵头、丝堵、碗形塞等不同密封方案，从成本角度选取碗形塞密封；采用冲出压强对比试验，识别出影响碗形塞密封效果的关键因子并确定碗形塞的最优方案：材料为S304、过盈量为0.167～0.272 mm、压入深度应为2.5～3.5 mm，密封胶品为T48。多轮发动机台架和整车道路试验表明，碗形塞密封方案完全可以应用于高性能发动机缸盖水套、油道等处的密封。

关键词：发动机；集成排气歧管；缸盖；水套；碗形塞

Abstract: In order to solve the sealing problem of the holes used in casting process for cylinder head,considering the application conditions of the sealing holes, different sealing, such as steel ball, tension plug, screw plug and sealing cap, are investigated.The sealing cap is selected because of cost. By adopting the impulse strength contrast test, the key factors are recognized which affects the sealing of the sealing cap and the optimal plan is determined:the material is S304, the interference is 0.167~0.272 mm, the pressure depth is 2.5~3.5mm, and the sealant is T48. Based on the several round test of engine bench and vehicle road test, the sealing cap can be applied to the sealing of high performance engine cylinder head water jacket and oil channel.

Keywords:engine; integrated exhaust manifold; cylinder head; water jacket; sealing cap

基于氧信号响应劣化补偿的三元催化器诊断

钟建伟,吴兴龙

泛亚汽车技术中心有限公司，上海201201

摘要：分析氧传感器劣化失效对三元催化器诊断的影响，发现前氧信号响应劣化导致三元催化器诊断计算的储氧时间变小，易导致将正常误判为故障；后氧信号响应劣化导致三元催化器诊断计算的储氧时间变大，易导致将故障误判为正常。引入前、后氧补偿值对实测储氧时间进行修正,设计基于氧传感器劣化的三元催化器诊断策略。试验表明，该策略可实现前后氧传感器劣化的偏差补偿，提高对三元催化器诊断的精确性。

关键词：氧传感器劣化；三元催化器诊断；氧传感器响应

Abstract:The effect of oxygen sensor degradation on the diagnosis of three way catalytic converter (TWC) is analyzed. It is found that the degradation of pre oxygen sensor leads to the decrease of oxygen storage time of TWC, which tends to misjudge the normal TWC as fault; while the deterioration of post oxygen sensor leads to the increase of oxygen storage time of TWC, which tends to misjudge the actual fault TWC as normal. The measured oxygen storage time is corrected by introducing the pre and post oxygen compensation values, and the diagnosis strategy of TWC based on the deterioration of oxygen sensor is designed. Experimental results show that the strategy can realize the deviation compensation of the deterioration of the pre and post oxygen sensors, and improve the accuracy of the TWC diagnosis.

Keywords:oxygen sensor degradation; TWC diagnostic; oxygen sensor response

天然气发动机EGR系统应用研究

张腾1，韩文涛2*，田占勇2，王林波2，安宁2，姚旺2

1.潍柴西港新能源动力有限公司，山东潍坊261061；2.潍柴动力股份有限公司，山东潍坊261061

摘要：研究进气流量传感器和废气文丘里流量计两种不同技术方案对废气再循环（exhaust gas recirculation，EGR）率控制精度的影响，并在采用理论空燃比的天然气发动机上进行试验验证。结果表明：基于废气流量计计算的EGR废气量精度更高，低速工况时相对误差小于4.27%，高速工况时相对误差小于0.35%；通过发动机台架EGR率测试，EGR率的相对误差小于2.64%，在可控范围内，且采用闭环控制策略，可保证EGR系统精准可靠地运行。

关键词：EGR系统；废气流量；EGR率；控制策略

Abstract:In order to explore the influence of two different technical schemes on the accuracy of EGR rate, intake flow sensor and exhaust venturi flowmeter are analyzed for a stoichiometric natural gas engine. The results shows that the accuracy of EGR gas volume calculated based on the exhaust air venturi method is more accurate. The error of EGR gas volume of the engine is 4.27% at low speed and within 0.35% at highspeed conditions. Engine test shows that the EGR rate error is within 2.64%. In addition, the EGR system adopted closedloop control strategy can make the operation of EGR system more accurate, reliable and stable.

Keywords:EGR system; exhaust gas flow; EGR rate; control strategy

高强化汽油机活塞裙部支撑疲劳开裂分析及结构改进

郭伟1,2，田维亮1,2，李猛猛1,2，董传成1,2，蔡恒1,2

1.滨州渤海活塞有限公司，山东滨州256602；2.山东省发动机活塞摩擦副重点实验室，山东滨州256602

摘要：针对某增压直喷高强化汽油机活塞在试验过程中出现的裙部支撑部位开裂问题，分析活塞材料、发动机运行过程及活塞结构强度，确定设计强度不足是裙部支撑部位开裂的主要原因，并对活塞销座两侧支撑部位进行改进优化。利用有限元仿真分析方法对设计优化方案进行模拟计算，结果表明：改进活塞裙部下端支撑筋的厚度及高度后，裙部下端支撑部位的疲劳系数可提高一倍以上；改进后的活塞样件顺利通过发动机耐久试验，验证了改进优化的有效性。该优化可以有效解决活塞裙部支撑部位开裂的问题，为增压直喷高强化汽油机活塞在该部位的细节设计及失效改进提供参考。

关键词：活塞裙部；有限元分析；裂纹；疲劳失效

Abstract:The piston material, engine running parameters and piston structural strength are analyzed in order to determine the main cause of the piston skirt support cracking for a turbocharged direct injection gasoline engine. It is determined that the design strength is the main reason for the skirt support part to crack, and the support parts on both sides of the piston pin seat are improved and optimized.The FEA is used for simulation and calculation.The results show that the fatigue factor is increasd more than double by strengthening the height and thickness of the skirt support.The improved pistons pass the engine endurance test successfully.The design optimization solves the problem of piston skirt support cracking effectively,it can provides a reference for the high strength gasoline engine piston design.

Keywords:piston skirt；finite element analysis；crack；fatigue failure

活塞结构参数对汽油机漏气量的影响

高尉尉1，2，王奇峰1,2, 陈丽1，2，马呈新1，2，王小田1，2

1.滨州渤海活塞有限公司，山东滨州256602；2.山东省发动机活塞摩擦副重点实验室，山东滨州256602

摘要：针对某汽油机出现的漏气量超标问题，对活塞裙部形线、销孔偏心、一环槽粗糙度及下侧面角度等活塞结构参数进行优化设计，利用动力学分析软件进行对比分析计算，得到改进活塞设计减少漏气量的优化方案。分析结果表明，活塞优化后，发动机总漏气量降低12.46%，有效解决汽油机漏气量超标的问题。台架试验验证动力学分析结果的正确性，优化方案可以为解决发动机漏气量超标问题提供理论依据。

关键词：汽油机；漏气量；活塞结构参数；动力学计算

IAbstract:In order to solve the problem of excess blowby for gasoline engine, the dynamic simulation is used to analyze the influence of piston structural parameters, such as skirt profile, pin bore offset, 1st groove roughness and lower side angle on engine blowby, and the optimization is carried out. The results show that the total blowby is reduced 12.46% which effectively solved the problem of excess blowby for gasoline engine. After bench test, the consistency of simulated analysis and the test results are verified. This optimization can provide theoretical basis for solving the engine overrun blowby.

Keywords:gasoline engine; blowby ; piston structural parameters; dynamic simulation