Types Of Power Units Research Articles

History of the scientific researches of the vehicles with hydrogen power units

BACKGROUND: Fuel cells are one of the promising directions in the development of electrified transport as it is capable of providing with mileage comparable to conventional vehicles powered by internal combustion engines, with no harmful emissions into the environment during the vehicle motion. The long-lasting process of development of fuel cells was associated with the inability to realize the potential of fuel cells and the availability of more accessible and reliable energy sources at that time. The present programs and measures to support electric vehicles and fuel cells set targets for reducing emissions of harmful gases and increasing the share of electric vehicles on the roads.
 AIMS: The study of the history of the development of fuel cells and their relevance to the use in vehicles.
 METHODS: The calculations to determine the specific parameters were performed with solving the differential equation of the force balance of vehicle motion using the numerical Euler method.
 RESULTS: The results of the scientific research are the determination of specific parameters of power units and the analysis of the history of the development of fuel cells. By comparing the specific parameters, it was revealed that the most effective are combined power units on fuel cells. When using these power units, a 2.5-fold decrease in mass was recorded compared to other types of power units.
 CONCLUSIONS: The use of fuel cells helps to reduce the weight of the power units and to improve the environmental safety of the vehicle. Fuel cells have undergone several long stages of development and reached their peak of development after the beginning of active space exploration. Currently, the development of hydrogen technologies is actively continuing, programs for the development of electrified transport have been issued in many countries, including the Russian Federation.
 The authors note the relevance of scientific research in this area and assume that vehicles powered by electrochemical generators will receive their further development in the coming years.

Modeling Processes of Emergence and Growth of Fractal Structures and Chamber Defects of Thermal Power Units. Part 2

The paper describes further development of model studies with the purpose to draw analogies of the occurrence of possible inhomogeneities and defects of the fractal type on the surface of various objects under the action of laser radiation for different conditions and schemes of a laser simulation experiment in comparison with real processes in the chambers of thermal machines due to the contacts of the working substances with their surface. The subject of this consideration is related to the fact that in laser schemes one can relatively easily and in a controlled manner to study their topology in various modifications (in the range of 0D–3D structures formed on surfaces of various geometric shapes of the fractal type). This provides great opportunities for studying various frequently occurring undesirable random defects and inhomogeneities of complex configuration with the development of unexpected processes in the dynamic modes of operation of various types of power units in their actual operation. This is determined by geometric analysis within the framework of the correspondding non-linear models with different non-linear fractal images. In this aspect, we have used two models to consider the development of emerging fractal fractured structures: first, diffusion propagation/growth of cracks of different geometry with a set of local segments and fragments in different directions; secondly, with diffusely limited aggregation of their distribution (Diffusion-Limited Aggregation – DLA) using the formalism of cellular automata in percolation approximation for different algorithms for the formation of fractal structures. We present only the final results of calculations without details of their procedure, which is sufficient for a visual and qualitative determination of the process of growth of fracturing and defects. In this case, the final goal of consideration is to study the emergence of possible and controllable local areas / collectors, starting from surface structures, and their association with real objects on the surface of chambers with a working substance in power systems. The possible practical significance of such modeling and analysis is discussed to forecast their working conditions.

Adjusting the service frequency of hybrid vehicles based on the use of diagnostics tools

Currently, traditional internal combustion engine vehicles are be-ing replaced by hybrid vehicles, which are more advanced and energy effi-cient than the former. According to the current technical regulation on the safety of wheeled vehicles, a hybrid is a vehicle that combines two types of power units in its design: an internal combustion engine and an electric mo-tor. The main advantage of these vehicles is the combination of efficiency and environmental friendliness. The trend towards an increase in the pro-duction of cars with hybrid power plants is due to a fundamental increase in the requirements of international standards for environmental safety and ef-ficiency of cars. In the coming years, the number of brands of cars with hy-brid power plants offered to the consumer by European, Chinese, Japanese, Korean, as well as domestic automakers would significantly increase in Rus-sia. The lack of scientifically based approaches to the organization of maintenance and repair of vehicles with hybrid power plants leads to a de-crease in the efficiency of the technical operation of this type of vehicle. Hence, there is a need to organize the maintenance of vehicles with hybrid power plants based on the optimization of maintenance modes. The choice of topic is justified by the possibility of improving the efficiency of opera-tion of vehicles with hybrid power plants.

Розробка методики визначення експлуатаційних витрат автобусів та тролейбусів із різними видами силових установок

This article proposes a methodology for calculating the unit operating costs of buses and trolleybuses with different types of power plants and presents the results of comparison between operation costs of buses with internal combustion engines, electric buses, conventional trolleybuses and ones equipped with autonomous driving. The object of the study are operating costs for buses and trolleybuses with different types of power units on the route with partial catenary absence for urban passenger transportation in normal modes of running. The objective of the study is to develop a methodology for comparative analysis of operating costs for buses and trolley buses with different types of power units and determine the feasibility and effectiveness of using different types of vehicles on the routes with partial autonomous driving. Research methods: mathematical modeling of operating costs formation for buses and trolleybuses with different types of power plants when used on the routes with partial catenary absence where it is necessary to use autonomous running. The structure of operating costs for urban passenger transportation is analyzed, revealing those that have the greatest impact on operating costs. The initial data base for the calculations is formed. A program for calculating unit operating costs per 1 km in Microsoft Excel for the route with partial autonomous driving was developed. The calculations show that using of trolleybuses with autonomous driving is more expensive than buses using at the same cost. We can achieve positive effect with a certain portion of autonomous driving, if the cost of autonomous trolleybuses are reduced compared to new vehicles cost, for example, due to rolling stock production by the enterprise. Keywords: comparison, operating costs, bus, trolleybus, autonomous driving, power plant, catenary, diesel generator, battery.

Comparative Economic Analysis for Different Types of Electric Vehicles

This study is dedicated to comparing the levelized operating costs of various types of power units and energy carriers for electric vehicles: battery systems, hydrogen-air fuel cells, and aluminum-air electrochemical generators. The operating cost considers the power unit itself, energy carrier, and associated charging infrastructure. Each electric vehicle type was calculated in two versions: a passenger electric car and a light duty commercial truck. It is shown that the most cost effective power unit is an aluminum-air generator. Its levelized operating cost is 1.5–2 times lower toward a battery system and 3–4 times lower toward fuel cells. The advantage of aluminum as energy carrier is the low cost and simple design of the corresponding power unit and charging infrastructure compared to those for battery and hydrogen power units. Aluminum recycling is key to its efficient use, this concept may become competitive in the aluminum-producing countries.

Discussion on RB technology and the application in 330MW unit

The RB function can automatically reduce the unit to a specified value after the main auxiliary equipment of the power plant is tripped to reduce the number of unit outages, which is beneficial to the stability of the power system. Based on the experiments of RB test on different types of power units, this paper makes research of RB technical problem, analyzes the characteristics of RB rapid load reduction and RB plan and test results in detail.

Exploring dependence of the patints’ radiation dose on the form of power supply voltage of x-ray tube

A brief analysis was conducted of organizational and technical methods of reducing the patient’s dose during radiographic examinations that are used in contemporary medicine. The paper considers optimization of the form of power supply voltage of X-ray tube as one of the efficient, but not sufficiently explored, areas of solving this problem. For its analysis, we propose a method of numerical simulation of the process of X-ray screening based on the experimentally obtained data. The results of experimental research are presented. Authors described the methods and results of calculation of influence of the form of power supply voltage of X-ray emitter on the total radiation dose of patients during medical examinations. To model the performance of several types of power units that operate on different physical principles, we created mathematical models that made it possible to calculate the instantaneous and integral values of all electrical parameters of X-ray tube, to find the integral dose of radiation in the plane of patient's location and to simulate a generalized reaction of the X-ray receiver of images on the ray flow that runs through the object of examination. Comparative analysis of the obtained results demonstrated that the total dose of radiation is significantly affected by the design and principle of operation of the power supply unit of X-ray tube, which is a part of the X-ray device. At the equivalent diagnostic quality of images, the difference in the X-ray dose of received by the patient in some modes may exceed 20 %. The assessment we performed indicates the feasibility of modernization of the outdated X-ray equipment with low frequency power units for the purpose of reducing the radiation dose through the improvement in the form of high voltage.

Generation Control Scheduling Model of Three Gorges Power Station during Non-Abandon Water Period

With types of power units, huge installed capacity and complicated operation modes, the Three Gorges Power Station (TGPS) is very important in network operation of Yangtze River area. Power forecasting of TGPS plays an important role in protecting the power network operation and shipping, especially for the short-term output forecasting. The water consumption rate of power station is one of the key conditions in short-term generation control system during non-abandon water period. Therefore, in order to develop the generation control scheduling model of TGPS in non-abandon water period, analysis on many factors should be put including: hydraulic turbine characteristic curves of cascade hydropower stations constructed by TGPS and the Gezhouba Power Station; discharge at dam site; water stage of relationship between upstream and downstream; and the last element is tailrace effect from the Gezhouba Power Station to TGPS. The historical operating result shows that the model referred has wide application prospect in production practice for high precision and much exercisable.

SIPRE Ice-Corer for Obtaining Samples from Permanently Frozen Bogs

Discusses the effectiveness of sampling devices demonstrated by summer 1962 field use in northern Yukon and laboratory tests in Mar. 1963. Hand drilling in Yukon Territory produced excellent cores, but the cutting teeth in the ice-corer were quickly dulled from mineral matter; holes 7-8 ft deep required three hrs drilling. Tests with power drives indicated that a two-man team could core a frozen bog 8 ft deep in 30-45 min. The two types of power units tested: a McCulloch chainsaw motor, and a Haynes earth drill, were both adequate; details are given.