A competing risk model for the reliability of cylinder liners in marine Diesel engines

In this paper, a competing risk model is proposed to describe the reliability of the cylinder liners of a marine Diesel engine. Cylinder liners presents two dominant failure modes: wear degradation and thermal cracking. The wear process is described through a stochastic process, whereas the failure time due to the thermal cracking is described by the Weibull distribution. The use of the proposed model allows performing goodness-of-fit test and parameters estimation on the basis of both wear and failure data. Moreover, it enables reliability estimates of the state of the liners to be obtained and the hierarchy of the failure mechanisms to be determined for any given age and wear level of the liner. The model has been applied to a real data set: 33 cylinder liners of Sulzer RTA 58 engines, which equip twin ships of the Grimaldi Group. Estimates of the liner reliability and of other quantities of interest under the competing risk model are obtained, as well as the conditional failure probability and mean residual lifetime, given the survival age and the accumulated wear. Furthermore, the model has been used to estimate the probability that a liner fails due to one of the failure modes when both of these modes act.     

Effect of the PLAZMAZER plasma ignition system on the fuel combustion regimes in combustion chambers of engines

An economically efficient method of combatting toxic products of incomplete fuel combustion in engines and other movable and stationary power installations by means of pulsed automatic control of the ignition and combustion processes carried out by the PLAZMAZER system is proposed. A new concept of the occurrence of motor knock in internal combustion engines with external carburetion, the stiff operating mode of diesel engines, erosion of turbine blades, burn-out of combustion-chamber and exhaust-line elements, and jet engine compression stalling are presented.     

Simultaneous removals of NOx, HC and PM from diesel exhaust emissions by dielectric barrier discharges

The main target of this work is to characterize the abatements of particulate matter (PM), hydrocarbons (HC) and nitrogen oxides (NO_x) from an actual diesel exhaust using dielectric barrier discharge technology (DBD). The effects of several parameters, such as peak voltage, frequency and engine load, on the contaminant removals have been investigated intensively. The present study shows that for a given frequency, the removals of PM and HC are enhanced with the increase of peak voltage and level off at higher voltage, while in the range of higher voltages a decline of NO_x removal efficiency is observed. For a given voltage, the maximums of specific energy density (SED) and removal efficiency are attained at resonance point. The increase of peak voltage will result in a significant decrease of energy utilization efficiency of DBD at most engine loads. Alkanes in soluble organic fraction (SOF) are more readily subjected to removals than polycyclic aromatic hydrocarbons (PAHs).     

Effect of advanced injection timing on the performance of natural gas in diesel engines

Concern over the environment and/or the increasing demand for conventional fossil fuel has promoted interest in the development of alternative sources of fuel energy for internal combustion (IC) engines. The effect of advanced injection timing on the performance of natural gas used as primary fuel in dual-fuel combustion has been examined. Satisfactory diesel engine combustion demands self-ignition of the fuel as it is injected near the top dead centre (TDC) into the hot swirling compressed cylinder gas. Longer delays between injection and ignition lead to unacceptable rates of pressure rise (diesel knock) because too much fuel is ready to burn when combustion eventually occurs. Natural gas has been noted to exhibit longer ignition delays and slower burning rates especially at low load levels hence resulting in late combustion in the expansion stroke. Advanced injection timing is expected to compensate for these effects. The engine has standard injection timing of 30° before TDC (BTDC). The injection was first advanced by 5.5° given injection timing of 35.5° BTDC. The engine ran for about 5 minutes at this timing and stopped. The engine failed to start upon subsequent attempts. The injection was then advanced by 3.5° (i.e. 33.5° BTDC). The engine ran smoothly on this timing but seemed to incur penalty on fuel consumption especially at high load levels.     

Effect of gas temperature on the gas loss from ventilated cavities

Summary. The theory for gas loss from ventilated cavities under isothermal conditions is extended to the non isothermal case, where the gas inside the cavity has a temperature different from the water temperature.     

用于测量柴油机气缸内碳粒浓度和火焰温度的光电系统

利用颗粒衍射原理,研制出一套用于测量柴油机气缸内局部瞬态碳粒浓度和火焰温度的光电测量系统。该系统采用分叉光纤,省去了一套复杂的光学分光组件。利用该测量系统对一台柴油机气缸内进行了相应测量,并分析了测量数据,结果表明活塞凹坑区的火焰温度和碳粒浓度相当高,在活塞的顶岸区,它们的循环变动很大。     

论16V265H型柴油机机体铸造工艺及改进

16V265H型柴油机是我公司引进美国EMD公司的新型柴油机。机体铸件是一个满足最大强度和刚度设计的整体铸造件,用来安装曲轴、凸轮轴、动力组和其他安装在柴油机上的部件,内部有主机油道和冷却水通道。由于结构复杂,机加工尺寸和形状精度很高,试制过程中存在很多难点问题。通过本文,介绍研制过程中,使用机体八箱劈模铸造工艺;CAD／CAM技术进行模具设计与制作;MAGMA软件铸造模拟等新方法、新工艺,解决工艺设计和生产过程中出现的问题。     

离心氮压机级间排气温度偏高的分析和排除

安钢制氧厂的C180M×3N2型和C150M×5N2型氮压机运行时存在级间排气温度偏高的现象,采取加固门形垫和优化在线清洗方法清洗后,级间排气温度正常。简介离心氮压机级间排气温度高的现象,介绍引起级间排气温度高的常见原因和处理方法,阐述处理效果和保证离心氮压机级间冷却器正常运行的其他措施。     

Diesel emission control system using combined process of nonthermal plasma and exhaust gas components' recirculation

A NO_x aftertreatment system, using nonthermal plasma (NTP) reduction and exhaust gas components' recirculation, is investigated. A pilot-scale system is applied to a stationary diesel engine. In this system, NO_x is first removed by adsorption, and subsequently, the adsorbent is regenerated by thermal desorption. NO_x desorbed is reduced by using nitrogen NTP. Moreover, NO_x, CO₂, and water vapor recirculated into the engine intake reduce NO_x. In this study, approximately 57% of the NO_x of the exhaust (NO_x: 240-325 ppm, flow rate = 300 NL/min) can be continuously treated for 58 h. A system energy efficiency of 120 g (NO₂)/kWh is obtained.     

Effect of reformulated fuel strategy on compression ignition engine compatibility using antioxidant additive and clean Karanja methyl ester

Clean Technologies and Environmental Policy - The present work aims at investigating the compatibility of antioxidant with biodiesel through the tribological assessment of a compression ignition...     

Effect of temperature and slope of a gas main in nonisothermal unsteady gas movement

The effect of the temperature and slope of a pipeline on the variation in gasdynamic parameters is studied using numerical methods.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 30, No. 4, pp. 619–624, April, 1976.     

Effect of the inhomogeneity of the temperature field in the screen cooled by exhaust gases on the efficiency of a cryostat

A quantitative estimate is obtained for the effect of the inhomogeneity of the temperature field in the cooled screen on the loss of material stored in a cryostat.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 32, No. 3, pp. 486–493, March, 1977.     

Effect of temperature and α-irradiation on gas permeability for polymeric membrane

In the present study the polyethersulphone (PES) membranes of thickness (35 ±2) μm were prepared by solution cast method. The permeability of these membranes was calculated by varying the temperature and by irradiation of α ions. For the variation of temperature, the gas permeation cell was dipped in a constant temperature water bath in the temperature range from 303–373 K, which is well below the glass transition temperature (498 K). The permeability of H₂ and CO₂ increased with increasing temperature. The PES membrane was exposed by a-source (₉₅Am₂₄₁) of strength (1 μ Ci) in vacuum of the order of 10⁻⁶ torr, with fluence 2.7 × 10⁷ ions/cm². The permeability of H₂ and CO₂ has been observed for irradiated membrane with increasing etching time. The permeability increases with increasing etching time for both gases. There was a sudden change in permeability for both the gases when observed at 18 min etching. At this stage the tracks are visible with optical instrument, which confirms that the pores are generated. Most of pores seen in the micrograph are circular cross-section ones.     

Effect of process temperature on the microstructure and properties of gas oxynitrocarburized 35CrMo alloy steel

In the present investigation, 35CrMo alloy steel was gas oxynitrocarburized at 550 °С, 570 °С and 610 °С for 2 h by applying a low-temperature gas multi-elements penetrating system. Microstructure, surface composition, case depth, microhardness, wear and corrosion resistance were analyzed. The compound layer consisting of γ′-Fe₄N and ε-Fe₃N and oxide layer of Fe₃O₄ and Fe₂O₃ were formed on the ground reference surface after treated. Compared with the conventional gas nitrocarburizing, a larger effective case depth was obtained successfully in a short time after treatment. The microhardness and the properties of wear and corrosion resistance were improved obviously and the properties of samples treated at 570 °C are optimum when compared with the samples treated at 550 °С and 610 °С for the same duration.     

中压天然气流量计实流标定中气体压力、温度的影响及控制方法

论述在中压天然气流量计实流标定中,调压及流量点调节弓{起检定用天然气各参数变化对测量准确度的影响。并讨论了中压天然气流量计实流标定中天然气压力和温度的控制调节方法,保证检定用天然气各参数的波动符合检定规程的要求。     

Effect of compression force, compression speed, and particle size on the compression properties of paracetamol.

The compression characteristics of two particle size fractions (< 90 microm, 105-210 microm) of paracetamol were examined. Each fraction produced extremely weak tablets and displayed a high tendency to cap. Low correlation coefficients of the initial parts of the Heckel plots, a low strain rate sensitivity, and an increase in mean yield pressure (from 34.2 to 45.5 MPa) with decrease in particle size all confirmed that the main mechanism during the compaction of paracetamol was fragmentation. The 105-210-microm particles underwent more fragmentation than the less than 90-microm powder. Heckel analysis confirmed that the larger size fraction of paracetamol produced denser compacts than the smaller fraction. The 105-210-microm fraction resulted in tablets with lower elastic recoveries and elastic energies. The elastic, plastic energy ratios indicated that the majority of energy involved during the compaction of paracetamol was utilized as elastic energy, indicative of massive elastic deformation of paracetamol particles under pressure.     

Effect of temperature on the formation of silicon nanoislands on noncrystalline substrates in microwave low-pressure gas discharge plasma

Conditions for the synthesis of nanodimensional silicon islands on noncrystalline substrates in microwave low-pressure gas discharge plasma have been studied in the case of weak interactions at the deposit-substrate interface. It is established that the formation of silicon nanoislands proceeds via the overgrowth (healing) of depressions on the initial substrate surface. The effect of temperature on the kinetics of nanoisland growth and the possibilities of controlling the parameters of nanoisland morphology are determined.     

便携式摩托车尾气分析仪的研制

介绍了自行研制的利用工业计算机主板实现的新型便携式摩托车尾气分析仪.该分析仪由采样系统、气体分析系统、辅助测量系统和显示系统组成.使用非扩散红外线(NDIR)光吸收方法分析HC、CO和CO2质量分数;使用电化学方法分析O2和NOx质量分数;采用磁电式感应器测量摩托车速度;热线式气体流量计测量尾气的流量.系统包括工业计算机主板、气体传感器、转速传感器、LCD显示屏、液晶屏、气体流量计、微型打印机等硬件部分和软件设计.研制的摩托车尾气分析仪能测量摩托车在各工况下的尾气排放状况.