CMI发动机燃油喷射系统工作原理及故障诊断技术分析

基于CMI发动机燃油喷射系统的系统构造,通过对该型发动机燃油喷射系统的驱动燃油泵、燃油计量组件、燃油分配器和燃油喷嘴等主要部件的系统构造和工作原理进行分析,深入阐述了该燃油喷射系统各部件的故障机制及故障表征现象,提供了该燃油喷射系统常见故障的诊断方法及故障排除措施,为该型发动机燃油喷射系统的日常维护、故障诊断及排除和故障预防提供了有力依据。     

电喷发动机燃油系统油路的故障检测

介绍了电喷发动机的优点及多点喷射的电喷发动机燃油系统的故障检测方法。通过对燃油系统起始油压、工作油压、加速油压、堵转油压及残余油压的检测即可判断出燃油系统油路的故障所在。     

某轮主机缸套异常磨粒磨损原因探讨

根据某轮主机缸套异常磨粒磨损的故障现象及故障发展过程,结合柴油机磨粒磨损机理,对该轮主机缸套异常磨粒磨损故障的原因进行了探讨与分析。分析表明：燃油中催化剂粉末含量偏高、燃油在贮存环节受到污染及燃油净化处理不当是造成此次故障的根本原因。据此提出了加强柴油机日常维护管理的措施。     

汽油机燃油修正及诊断的失效模式探讨

分析了汽油机排放闭环控制的基本原理,以及根据氧传感器电压信号进行的燃油修正的基本原理,阐明了短期燃油修正和长期燃油修正之间的关系,以及燃油修正诊断的基本逻辑。并针对燃油修正诊断故障进行了举例说明,对于燃油修正诊断的故障排查进行了一定的探讨。     

某船用主机燃油系统泄漏故障分析与处理

针对某船主机燃油系统排气温度偏差大、燃油进机连接管泄放管路泄漏量大的故障,根据检修过程并结合喷油器定期解体保养情况,对故障原因进行了分析。结果表明:故障的主要原因为燃油系统管系部件密封性差。据此,对安装和检修提出针对性建议。     

双联可切换燃油粗滤器的研制与运用

针对DFa型机车柴油机燃油系统燃油压力低故障频繁发生的问题,在分析其原因的基础上,研制了双联可切换燃油粗滤器。该粗滤器具有通用性好、过滤效率高、使用寿命长、环保性能好和故障切换方便等特点,并在运用中取得了良好效果。     

根据喷油压力波形特征判断燃油喷射装置故障部位

通过ZB-2型柴油机燃油喷射系统故障诊断仪(即柴油机燃油压力波检测仪)对DF4型机车柴油机燃油压力波的检测,在对大量检测事例进行跟踪、统计、分析的基础上,揭示出燃油压力波的检测波形与该缸喷射装置质量状态的对应关系,并据此确定故障部位,为故障处理提供参考.     

柴油机燃油系的故障分析

柴油机燃油系的故障分析贵州农学院农业工程系张宇光１引言柴油机燃油系的工作状况对柴油机的动力性、经济性影响极大。燃油系工作一旦失常，柴油机便会出现一系列相应的故障。怎样迅速正确地分析判断与处理故障，是生产实际中经常遇到的问题。本文主要从燃油系的基本功能...     

某型辅机增压器喘振故障分析与排除

针对某型辅机柴油机结构及其燃油系统特点,对其增压器喘振故障现象进行了分析,发现造成此次故障的主要原因是柴油机燃油系统故障,据此制定维修方案并排除了故障。     

6FA燃气轮机试车台燃油控制阀性能研究

对6FA燃气轮机试车台的燃油控制阀进行性能研究,阐述了试车台燃气轮机燃油组成、燃油控制阀的性能和故障反馈等。通过阀门的性能特性曲线和执行机构的性能分析,重点讨论了6FA燃气轮机试车台的燃油控制阀位置控制和反馈性能,并对燃油控制阀在运行过程中会出现的故障以及反馈动作进行探讨。试车台的燃料选用与目前燃气轮机电站所用的天然气燃料不同,对6FA燃气轮机试车台燃油控制阀的性能分析,可为同类型燃气轮机试车台的燃油系统搭建提供借鉴和参考。     

Matching of a DC motor to a photovoltaic generator using a step-upconverter with a current-locked loop

A photovoltaic (PV) generator is a nonlinear device having insolation-dependent volt-ampere characteristics. Because of its relatively high cost, the system designer is interested in optimum matching of the motor and its mechanical load to the PV generator so that maximum power is obtained during the entire operating period. However, since the maximum-power point varies with solar insolation, it is difficult to achieve an optimum matching that is valid for all insolation levels. In this paper it is shown that for maximum power, the generator current must be directly proportional to insolation. This remarkable property is utilized to achieve insolation-independent optimum matching. A shunt DC motor driving a centrifugal water pump is supplied from a PV generator via a step-up converter whose duty ratio is controlled using a current-locked feedback loop     

Natural convection of a non-Newtonian fluid about a horizontal cylinder and a sphere in a porous medium

The problem of natural convection of a non-Newtonian fluid about a horizontal isothermal cylinder and an isothermal sphere in the porous medium is considered. The present study is based on the boundary layer approximation and only suitable for a high Rayleigh number. Similarity solutions are obtained by using the fourth order Runge-Kutta method. The effects of the wall temperature T_W and the new power-law index n on the characteristics of heat transfer are discussed.     

Exploration of heat transfer effect in a magnetohydrodynamics flow of a micropolar fluid between a porous and a nonporous disk

An analysis is carried out for the flow characteristics of a conducting micropolar fluid. The fluid was passed in between two parallel disks of infinite radii. The novelty of the study is to consider one of the disks as porous and the other one as nonporous, and the external magnetic field is applied along the transverse direction of the flow. The flow phenomena for the polar fluid characterized by the magnetic effect in conjunction with the temperature equation reduce to a set of coupled nonlinear ordinary differential equations using the requisite transformations and nondimensionalization. An analytical approach such as the variation parameter method is employed to tackle the system efficiently. To emphasize the effect of various physical parameters contributing to the flow phenomena, that is, non-zero tangential slip, Reynolds number, Prandtl number, magnetic parameter, and material parameter on the flow profiles of axial and radial velocities, the microrotation and temperature profiles are presented graphically. To validate the simulated results, a comparison with established results is made, and it is concluded that both are in good correlation.     

Evaporating characteristics of a microlayer under a bubble

Using the Hallinan‐Ervin model, the flow and evaporation in a bubble microlayer were theoretically analyzed, and the dryout characteristics and Staub's criterion were discussed in detail. It was revealed that the critical dryout radius is associated with the wettability of the heated surface, and that the dominant role for microlayer evaporation is disjoining pressure, not surface tension gradient. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(6): 456–462, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10052     

Solidification of a liquid about a cylindrical pipe

The temperature distribution and the rate of removal of heat by a coolant are predicted for the process of solidification of a liquid about a cold, isothermal pipe. The heat balance integral method incorporating spacial sub-division is used. It is found that acceptable results can be obtained by using only a small number of sub-divisions together with a piece-wise, linear profile. Furthermore, the results illustrate that the sensitivity which is normally associated with the heat balance integral method is overcome.     

Stability of a multi-machine system incorporating a superconductingalternator

A preliminary study on the transient behavior of a superconducting turbo-alternator in a typical multimachine system is described. The study covers the effect of conventional controllers, power-system stabilizers and phase advance networks. The open-loop response of the system is compared to the response when the superconducting alternator is replaced by its conventional counterpart     

Bioconvection in a squeezing flow of a micropolar fluid in a horizontal channel

The bioconvection flow of an incompressible micropolar fluid containing microorganisms between two infinite stretchable parallel plates is considered. A mathematical model, with a fully coupled nonlinear system of equations describing the total mass, momentum, thermal energy, mass diffusion, and microorganisms is presented. The governing equations are reduced to a set of nonlinear ordinary differential equations with the help of suitable transformations. The resulting nonlinear ordinary differential equations are linearized using successive linearization method, and the resulting system of linear equations is solved using the Chebyshev collocation method. The detailed analysis illustrating the influences of various physical parameters, such as the micropolar coupling number, squeezing parameter, the bioconvection Schmidt number, Prandtl numbers, Lewis number, and bioconvection Peclet number on the velocity, microrotation, temperature, concentration and motile microorganism distributions, skin friction coefficient, Nusselt number, Sherwood number, and density number of motile microorganism, is examined. The influence of the squeezing parameter is to increase the dimensionless velocities and temperature and to decrease the local Nusselt number and local Sherwood number. The density number of motile microorganism is decreasing with squeezing parameter, bioconvection Lewis number, bioconvection Peclet number, and bioconvection Schmidt number.     

Hydrothermal Behavior of a Ferrofluid in a Corrugated Channel in the Presence of a Magnetic Field

In this paper, results of applying a non‐uniform magnetic field on a dilute ferrofluid (water and 3% vol. Fe₃O₄) flow in a corrugated channel under a constant heat flux boundary condition have been reported. The thermal behavior of the flow is investigated numerically using a two‐phase mixture model and control volume technique. It is concluded that using a magnetic field with a negative gradient on a nanofluid flow in corrugated channels can be proposed as a suitable method to achieve higher heat transfer performance and augment the heat transfer coefficient and also reduces the wall temperature. This method can lead to the design of more compact heat exchangers. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(1): 80–92, 2014; Published online in Wiley Online Library ( wileyonlinelibrary.com/journal/htj ). DOI 10.1002/htj.21060     

The limiting characteristics of a cascade photoconverter of a new type based on a homogeneous semiconductor

A homogeneous planar photoconverter (PC) of a new type based on a multi-junction n-p-p ⁺-n-p-p ⁺-...-n-p-p ⁺ semiconductor structure was proposed. This semiconductor structure is a cascade PC consisting of several exposed PCs connected in series, with the light passing through the previous semiconductor layers. A theory was worked out, and the limiting values of photoelectric and energy characteristics of high-voltage devices that convert monochromatic and solar light were developed. These values include optimum values of the thickness and the number of the PCs applied onto the base PC, spectral selectivity, voltage-current characteristics, and performance. The no-load voltage rises practically in a linear fashion when the number of cells in the cascade increases. With an optimum number of cells, the peak performance values reach their peaks and considerably exceed the performance of the base PC, especially at a low carrier collection coefficient in the base PC.