Design and dynamic characteristic prediction of air-powered twin-rotor piston engine

A novel air-powered twin-rotor piston engine(ATPE) utilizing a differential velocity driving mechanism to achieve a high output torque was proposed.The ATPE had eight separated rotary cylinders which can dynamically enlarge the engine displacement as a result of the special driving mechanism,which was named dynamic volume expansion.The mathematical model of ATPE comprising a dynamic model and a thermodynamic model was established under the assumption of no mechanical friction.The model was numerically simulated in Matlab.The results show that shortage of low output torque confusing traditional air-powered engines can be overcome.The average output torque sharply increases to 100 N·m,which is about three times that of traditional air-powered engines with equal cylinder displacement under the pressure of 0.6 MPa at 480 r/min.ATPE can be used to drive vehicles directly without transmission box,therefore the energy transfer efficiency of ATPE can be increased.Furthermore,benefitting from the novel gas distribution system,the engine shows an ability in self-adjusting under different loads.The arrangements of air ports automatically adjust the open interval of air ports according to the load,which may simplify the speed control system.

Review of Power Supply and Distribution Construction Technology for Highway Electromechanical Engineering

In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.

Novel Oxygen Storage Components Promoted Palladium Catalysts for Emission Control in Natural Gas Powered Engines

A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.

Recent advance on the efficiency at maximum power of heat engines

This review reports several key advances on the theoretical investigations of efficiency at maximum power of heat engines in the past five years. The analytical results of efficiency at maximum power for the Curzon-Ahlborn heat engine, the stochastic heat engine constructed from a Brownian particle, and Feynman＇s ratchet as a heat engine are presented. It is found that： the efficiency at maximum power exhibits universal behavior at small relative temperature differences; the lower and the upper bounds might exist under quite general conditions; and the problem of efficiency at maximum power comes down to seeking for the minimum irreversible entropy production in each finite-time isothermal process for a given time.

Integration optimization of novel electric power steering system based on quality engineering theory

The dynamic model of a novel electric power steering （EPS） system integrated with active front steering function （the novel EPS system） is built. The concepts and quantitative expressions of the steering road feel, steering sensibility, and steering operation stability are introduced. Based on quality engineering theory, the optimization algorithm is proposed by integrating the Monte Carlo descriptive sampling, elitist non-dominated sorting genetic algorithm （NSGA-II） and 6-sigma design method. With the steering road feel and the steering portability as optimization targets, the system parameters are optimized by the proposed optimization algorithm. The simulation results show that the system optimized based on quality engineering theory can improve the steering road feel, guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the novel electric power steering system.

Groundwater Waves in a Coastal Fractured Aquifer of the Third Phase Qinshan Nuclear Power Engineering Field

Tidal fluctuations of Hangzhou Bay produce progressive pressure waves in adjacent field fractured aquifers, as the pressure waves propagate, groundwater levels and hydraulic gradients continuously fluctuate. The effect of tidal fluctuations on groundwater flow can be determined using the mean hydraulic gradient that can be calculated by comparing mean ground and surface water elevations.Tidal fluctuation is shown to affect the piezometer readings taken in a nearshore fractured aquifer around the nuclear power engineering field. Continuous monitoring of a network of seven piezometers provided relations between the tidal cycle and the piezometer readings. The relations can be expressed in times of a time and amplitude scaling factor. The time lag and the tidal efficiency factor and wavelength are calculated using these parameters. It provides significant scientific basis to prevent tide and groundwater for the nuclear power engineering construction and safety run of nuclear power station in the future.

Research on Coordinated Development and Optimization of Distribution Networks at All Levels in Distributed Power Energy Engineering

The uncertainty of distributed generation energy has dramatically challenged the coordinated development of distribution networks at all levels.This paper focuses on the multi-time-scale regulation model of distributed generation energy under normal conditions.The simulation results of the example verify the self-optimization characteristics and the effectiveness of real-time dispatching of the distribution network control technology at all levels under multiple time scales.

Reciprocating Engine Step Load Response in Islanded Power Generation

The step load response of reciprocating engines is one of the key characteristics when considering its application in medium to large scale stationary power generation especially with islanded generation. This paper discusses the impacts of power frequency deviation on the generators and electrical equipment in the network and presents the relationship between step load capabilities and generator operating parameters. For a power plant consisting of a number of generators both step load and power output requirements must be satisfied. An analysis method is proposed to facilitate the development of an operation strategy which can meet both step load and power demand requirements in the full load range.? Typical reciprocating engine step load curves are used to demonstrate the analysis method and the results are further optimised for lower operational cost. This analysis method provides a general approach to operation strategy of large reciprocating engines used in islanded power generation.

Ecosystem Service Value of Jingtaichuan Electric Power Irrigation Engineering

The ecosystem service value of Jingtaichuan electric power irrigation engineering( referred to as Jingdian engineering) was divided into internal value( the value of farmland system,shelter forest system outside of farmland and wetland waters) and external value( the ecological service value of ecological migration to the vegetation restoration of the Qilian Mountains) firstly,and then it was analyzed by using the model method and the factor equivalent method. The results showed that the internal ecological service value of Jingdian engineering was 36. 3 ×10~8 yuan,which was 25. 0 times larger than the total annual cost. The external ecological service value was 40. 05 ×10~8 yuan,which was 27. 6 times larger than the total annual cost. Among the three functional systems,the ecological service value of farmland system was the largest. The ecological service value of farmland system was mainly reflected in waste disposal,wind prevention and sand fixation,and food production. The external ecological service value was mainly the ecological service value of migration to vegetation restoration in the Qilian Mountains. Jingdian engineering is the only highlifting project that raises water to the desert in China. It transfers water from outer basins to control desertification and provides a successful road for ecological migration and desertification control in arid areas.

Application of Space-time Conservation Element and Solution Element Method in Intake and Exhaust Flows of High Power Density Diesel Engine

A one-dimensional pipe flow model of single-cylinder diesel engine is established to investigate the intake and exhaust flow characteristics of diesel engine in the condition of high power density(HPD).A space-lime conservation element and solution element(CE/SE)method is used to derive the discrete equations of the partial differential equation for the intake and exhaust systems.The performance parameters of diesel engine with speed of 2100 r/min are simulated.The simulated results are in accordance with the experimental data.The effect of increased power density on charging coefficient is analyzed using a validated model.The results show that the charging coefficient is slowly improved with the increase in intake pressure,and is obviously reduced with the increase in engine speed.

Unit stream power,minimum energy dissipation rate,and river engineering

Unit stream power is the most important and dominant parameter for the determination of transport rate of sand,gravel,and hyper-concentrated sediment with wash load.Minimum energy dissipation rate theory,or its simplified minimum unit stream power and minimum stream power theories,can provide engineers the needed theoretical basis for river morphology and river engineering studies.The Generalized Sediment Transport model for Alluvial River Simulation computer mode series have been developed based on the above theories.The computer model series have been successfully applied in many countries.Examples will be used to illustrate the applications of the computer models to solving a wide range of river morphology and river engineering problems.

Research on H_2 speed governor for diesel engine of marine power station

The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H, speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.

Development of nuclear power plant real-time engineering simulator

A nuclear power plant real-time engineering simulator was developed based on general-purpose ther- mal-hydraulic system simulation code RELAP5. It mainly consists of three parts:improved thermal-hydraulic system simulation code RELAP5,control and protection system and human-machine interface. A normal transient of CHASHMA nuclear power plant turbine step load change from 100% to 90% of full power,was simulated by the en- gineering simulator as an application example. This paper presents structure and main features of the engineering simulator,and application results are shown and discussed.

Effects of Hydrogen Addition on Power and Emissions Outputs from Diesel Engines

Energy efficiency and environmental impact have become dominant topics in internal combustion engines development. Among many strategies to improve power and emissions outputs from diesel engines is the partial mix of hydrogen and air as fresh charge components to form extremely lean and homogenous mixture, which resist the spontaneous combustion, while diesel fuel is injected directly inside combustion chamber using the conventional fuel injection systems. This contribution presents an analytical and experimental investigation for the effects of adding hydrogen on diesel engines power output and the reduction of emissions. Parametric analysis is used based on lamped parameters modeling of intake manifold to estimate in cylinder trapped charge. The fuel energy flow to engine cylinders is compared for a range of loads and concentrations to simulate relevant case studies. Diesel fuel reduction for significant range of part-load operation can be achieved by introducing hydrogen, along with power improvement emission reductions are affected positively as well. This is achievable without compromising the engine maximum efficiency, given that most engines are operated at small and part-load during normal driving conditions, which allow for introducing more hydrogen instead of large quantities of excess air during such operation conditions that also can be further improved by charge boosting.

ENERGIZING MYANMAR--A Chinese company builds Myanmar’s largest internal combustion engine power plant

“According to the license issued by the power supply authority, the electricity supply is 220V, load current 16 amperes and maximum power 3,000 watts,” reported Kyaw Zaw Win, manager of Eternal Hotel in Kyaukse, a township about 40 kilometers south of Mandalay in northern Myanmar. The hotel has been open since last year and has maintained an occupancy rate of 80 percent.“Our hotel can operate dozens of air conditioners at the same time without any problem.

Engineering Geological Study of Regional Tectonic Stability in the Area of the Longyang Gorge Power Station on the Huanghe (Yellow) River

In the stability study of the regional structures in the area of the Longyang Gorge Hydroelectrical Power Station, a model of the current stress-deformation field of the area was constructed based on analyses of available data of regional surveys and historical earthquakes and field investigations of active faults and ancient earthquakes. This model was examined and verified by physical and mathematical simulation experiments, and quantitative relations and data were obtained.

Discussion on Project Management Mode and Power Engineering Management

In view of the current development of power engineering management,traditional management methods can no longer be applied to the management of current power engineering work.Therefore,it is necessary to innovate and optimize existing project management modes,transform traditional management concepts and models,focus on addressing the problems in project management and improve management.This paper mainly analyzes the project management mode and power engineering management.

Discussion on the Application of Complex Power Network to Software Engineering

Along with the further development of science and technology, computer hardware and the Intemet are in a rapid development, and information technology has been widely used in all fields so that complex problems are simply solved. Because of the needs for the development, software starts to mutually integrate with complex power network, making the scale of software increase greatly. Such a growing trend of software promotes soft-ware development to go beyond a general understanding and control and thus a complex system is formed. It is necessary to strengthen the research of complex network theory, and this is a new way to help people study the complexity of software systems. In this paper, the development course of complex dynamic network is introduced simply and the use of complex power network in the software engineering is summarized. Hopefully, this paper can help the crossover study of complex power network and software engineering in the future.

Repacking practice for G-3 engineering driller power unit with drive shaft of dual channel reverse circulation

In order to satisfy operating requirements for constant core drilling technology in reverse circulation with hollow-through DTH,the power unit of G-3 engineering driller was ameliorated. The new one with dual channel drive shaft, achieved the perfect assemble with transmission structure of the original power unit. It could interconvert according to need by using two sets of drive shafts with direct and reverse circulation. The repacked G-3 engineering driller carried on experiment in the field test in Luanchuan molybdenum mine of Henan, whose effect was very good.