scholarly journals IMPROVING METHODS OF THERMAL PREPARATION OF SHIP POWER PLANTS

Author(s):  
Victor Ivanovich Kochergin

Low ambient temperatures negatively impact the performance criteria of the ship power plants: increasing load onto the moving parts due to the growing irregularity of the shaft rotation speed in the power plants . Heating of a power plant in cold seasons is especially important for the modes of hot idle time, which are typical for all kinds of transport. Negative impact of low ambient temperatures most notably becomes apparent at starting the internal combustion engines. Normative documents do not determine the size of harmful substance discharge during the engine operation in the reset mode. To maintain the optimum thermal condition of the ship power plants for the purpose of ensuring their profitability, non-failure operation and resource indicators it is necessary to develop and widely use the thermal preparation methods. As the main criteria of such improvement it is possible to use the following indicators: efficiency of thermal preparation, amount of power inputs, labor intensiveness during installation, mobility, environment protection and fire safety. Pre-start heating units on the base of catalytic heating elements meet the required quality criteria of thermal preparation of power plants, especially regarding the environmental friendliness of the process. The problem of preliminary evaporation of liquid fuel has been solved. Pilot studies of the catalytic heating elements operating on gas or diesel fuel with preliminary evaporation have defined the potential of catalytic oxidation technologies. The results obtained allow further development of ecologically safe and effective pre-starting preheaters that use diesel fuel as a source of thermal energy and the most widespread type of fuel for ship power plants.

Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified.


2019 ◽  
pp. 134-140
Author(s):  
A.A. Orekhov ◽  
S.V. Timokhin ◽  
I.A. Spitsyn ◽  
K.Z. Kuhmazov

В работе рассмотрены особенности эксплуатации автомобилей при низких температурах окружающего воздуха, а также существующие способы и средства тепловой подготовки их агрегатов. Если вопросы тепловой подготовки и поддержания рационального температурного режима двигателей внутреннего сгорания автомобилей в значительной степени решены, то для агрегатов их трансмиссий они требуют дальнейшего развития. Проанализировано применение тепловых аккумуляторов для тепловой подготовки агрегатов автомобилей. Предложен способ и система обеспечения рационального температурного режима коробки передач автомобиля КамАЗ с использованием теплового аккумулятора фазового перехода. Сформулированы цель и задачи исследований. Проведен расчет объема теплоаккумулирующего материала, необходимого для подогрева трансмиссионного масла коробки передач автомобиля КамАЗ до рациональной температуры в условиях зимней эксплуатации. Разработаны гидравлическая и функциональная схемы системы регулирования температуры масла в коробке передач автомобиля КамАЗ с тепловым аккумулятором фазового перехода, применение которой обеспечит быстрый выход на рациональный температурный режим коробки передач автомобиля и его стабилизацию как в зимнее, так и в летнее время года и, тем самым, снизит износ деталей, механические потери в коробке передач, расход топлива автомобилем.The paper discusses the features of operation of cars at low ambient temperatures, as well as existing methods and means of heat treatment of their units. If the issues of thermal preparation and maintaining a rational temperature regime of automobile internal combustion engines are largely resolved, then for the units of their transmissions they require further development. The application of heat accumulators for the thermal preparation of automobile units is analyzed. A method and system for ensuring a rational temperature regime of a KamAZ car gearbox using a phase transition heat accumulator is proposed. The purpose and objectives of research are formulated. The calculation of the volume of heat-accumulating material necessary for heating the gear oil of a KamAZ car gearbox to a rational temperature in winter conditions has been carried out. A hydraulic and functional diagram of the oil temperature control system in a KamAZ car gearbox with a phase-transfer heat accumulator has been developed, the use of which will provide quick access to the rational temperature regime of the car gearbox and its stabilization in both winter and summer seasons and, thereby, reduce wear of parts, mechanical losses in the gearbox, fuel consumption by the car.


Trudy NAMI ◽  
2022 ◽  
pp. 53-59
Author(s):  
A. N. Kozlov ◽  
M. I. Araslanov

Introduction (problem statement and relevance). The depletion of oil fuels reserves and the steady growth of their consumption will require new solutions in the development of technologies based on renewable energy sources. The study of the possible alternative fuels use in internal combustion engines is a complex scientific task, including the research of the alternative fuels effect on the power plants operation efficiency.The purpose of the study was to obtain the speed characteristics of a diesel engine operating on ethyl alcohol and rapeseed oil.Methodology and research methods. An air-cooled with volumetric mixture formation tractor diesel engine of dimension 2Ch 10.5/12.0 was selected as an object of research. The study was carried out by a comparative method. To measure the speed characteristic a fixed cyclic fuel supply was applied after the engine reaching the nominal operating mode at a crankshaft speed of 1800 min-1 and an average effective pressure in the cylinder of 0.588 MPa. This approach, with the all-mode regulator of the fuel pump turned off, made it possible to identify the main regularities of intra-cylinder processes at different speed modes of engine operation.Scientific novelty and results. The article presents the bench tests results of a diesel engine operating at various speed modes on ethanol and rapeseed oil, and analyzes in detail the main indicators of the combustion process and the effective engine performance in comparison to the use of traditional fuel. The practical significance lies in the possibility of using the obtained results to improve the diesel engines operation on alternative renewable fuels.


Author(s):  
Seyed Navid Shahangian ◽  
Mojtaba Keshavarz ◽  
Ghasem Javadirad ◽  
Nader Bagheri ◽  
Seyed Ali Jazayeri

HCCI engines have low emission and high efficiency values compared to the conventional internal combustion engines. These engines can operate on most alternative fuels such as dimethyl ether (DME), which has been tested as a possible diesel fuel for its simultaneously reduced NOx and PM emissions. HCCI combustion of both DME and n-heptane fuels display a distinct two-stage ignition reaction with the first stage taking place at fairly low temperatures and the second stage taking place at high temperatures. The second stage is responsible for the main stage of the heat release process. In this study, a single-zone, zero-dimensional, thermo-kinetic combustion model has been developed. MATLAB software is used to predict engine performance characteristics of HCCI engines using two types of diesel fuel: Dimethyl ether and N-heptane. The effects of intake temperature and pressure, fuel loading and addition of EGR gases on auto-ignition characteristics, optimum combustion phasing, and performance of the HCCI engines are considered in this study. Simultaneous effects of these variables for finding the most appropriate regime of HCCI engine operation, considering knock and misfire boundaries, are also investigated.


Author(s):  
Petar Kazakov ◽  
Atanas Iliev ◽  
Emil Marinov

Over the decades, more attention has been paid to emissions from the means of transport and the use of different fuels and combustion fuels for the operation of internal combustion engines than on fuel consumption. This, in turn, enables research into products that are said to reduce fuel consumption. The report summarizes four studies of fuel-related innovation products. The studies covered by this report are conducted with diesel fuel and usually contain diesel fuel and three additives for it. Manufacturers of additives are based on already existing studies showing a 10-30% reduction in fuel consumption. Comparative experimental studies related to the use of commercially available diesel fuel with and without the use of additives have been performed in laboratory conditions. The studies were carried out on a stationary diesel engine СМД-17КН equipped with brake КИ1368В. Repeated results were recorded, but they did not confirm the significant positive effect of additives on specific fuel consumption. In some cases, the factors affecting errors in this type of research on the effectiveness of fuel additives for commercial purposes are considered. The reasons for the positive effects of such use of additives in certain engine operating modes are also clarified. Key words: diesel fuel, diesel fuel additives, engine efficiency.


2020 ◽  
Vol 15 (10) ◽  
pp. 1357-1363
Author(s):  
A.A. Panfilov ◽  
◽  
I.S. Vokhmyanin ◽  

The paper presents the rationale for the feasibility of using an autonomous liquid heater for thermal preparation of the engine in different climatic zones. A comparison is made of operating costs when using an autonomous liquid heater and a car alarm with the function of maintaining the optimum temperature. Several large settlements of the Tyumen region were selected for a comparative calculation. Using climatic portals, the average number of cold days over three years was selected and the number of cold engine starts in each city was determined. The objects of the study were Toyota Land Cruiser Prado cars with different power plants: diesel and gasoline. The calculation does not consider the effect of the autonomous heater on the comfort of use and the technical condition of the vehicle, only the current fuel costs during daily operation are taken into account. In the course of the calculations, it was found that at ambient temperatures up to -150C for a gasoline car and -170C for a diesel car, the use of a pre-starting autonomous liquid heater is not economically viable. The required number of days is also determined to obtain economic benefits from the pre-heater, taking into account the cost of its installation on cars with gasoline and diesel engines. Using the results of the study, it can be concluded that not in all settlements it is advisable to install preheaters. The severity of the climate in some cities does not pose a big threat to a guaranteed cold engine start and may be limited only by using the remote engine start function built into the security system.


Author(s):  
Alexey Muratov ◽  
Andrey Balakin ◽  
Denis Bardin ◽  
Valentina Tselikovskaya ◽  
Leyla Kurmanova

Objective: Studying the effect of diesel locomotives on the use of natural gas as motor fuel. Identification of the main advantages of using natural gas in internal combustion engines. Analysis of the effect of gas engine fuel on the performance of diesel locomotive power plants. Methods: Simulation of the working process of two engines: the first – on diesel fuel, the second – on the gas mixture. Adjustment of the mathematical model according to the real parameters of 1А-5Д49-2 diesel engine, taken during the rheostat tests of 2ТЭ116 diesel locomotive. Conducting calculation and experimental studies to assess the effect of the complete replacement of diesel fuel with natural gas on the operation of the locomotive power plant; accumulation of computational and experimental data, their systematization and statistical analysis. Theoretical dependences of the change in the specific effective fuel consumption of a diesel engine operating on natural gas through the gas cycle on the position of the driver’s controller, as well as dependences of the change in the effective performance of a diesel engine have been discussed. The calculated values are compared for the diesel engine operating on natural gas and the diesel engine operating on diesel fuel. Results: The calculated dependencies of the performance of Series 1А-5Д49-2 (16ЧН26/26) diesel engine of 2ТЭ116 diesel locomotive with the use of gas engine fuel have been obtained. The obtained data has been analyzed allowing carrying out theoretical estimation of efficiency of natural gas used as gas engine fuel throughout the entire operating range of 1А-5Д49-2 (16ЧН26/26) diesel engine of 2ТЭ116 diesel locomotive. A conclusion was confirmed about the expediency and efficiency of using natural gas in railway transport, particularly diesel locomotives. The influence of replacement of diesel fuel with natural gas on the performance indicators of diesel locomotives has been determined. Practical importance: The obtained dependencies will help in forecasting and in the theoretical evaluation of the feasibility of using natural gas as a motor fuel for locomotive power plants.


Author(s):  
Andreas A. Malikopoulos ◽  
Panos Y. Papalambros ◽  
Dennis N. Assanis

Advanced internal combustion engine technologies have afforded an increase in the number of controllable variables and the ability to optimize engine operation. Values for these variables are determined during engine calibration by means of a tabular static correlation between the controllable variables and the corresponding steady-state engine operating points to achieve desirable engine performance, for example, in fuel economy, pollutant emissions, and engine acceleration. In engine use, table values are interpolated to match actual operating points. State-of-the-art calibration methods cannot guarantee continuously the optimal engine operation for the entire operating domain, especially in transient cases encountered in the driving styles of different drivers. This article presents brief theory and algorithmic implementation that make the engine an autonomous intelligent system capable of learning the required values of controllable variables in real time while operating a vehicle. The engine controller progressively perceives the driver’s driving style and eventually learns to operate in a manner that optimizes specified performance criteria. A gasoline engine model, which learns to optimize fuel economy with respect to spark ignition timing, demonstrates the approach.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.


2021 ◽  
pp. 146808742098626
Author(s):  
Pooyan Kheirkhah ◽  
Patrick Kirchen ◽  
Steven Rogak

Exhaust-stream particulate matter (PM) emission from combustion sources such as internal combustion engines are typically characterized with modest temporal resolutions; however, in-cylinder investigations have demonstrated significant variability and the importance of individual cycles in transient PM emissions. Here, using a Fast Exhaust Nephelometer (FEN), a methodology is developed for measuring the cycle-specific PM concentration at the exhaust port of a single-cylinder research engine. The measured FEN light-scattering is converted to cycle-resolved soot mass concentration ([Formula: see text]), and used to characterize the variability of engine-out soot emission. To validate this method, exhaust-port FEN measurements are compared with diluted gravimetric PM mass and scanning mobility particle sizer (SMPS) measurements, resulting in close agreements with an overall root-mean-square deviation of better than 30%. It is noted that when PM is sampled downstream in the exhaust system, the particles are larger by 50–70 nm due to coagulation. The response time of the FEN was characterized using a “skip-firing” scheme, by enabling and disabling the fuel injection during otherwise steady-state operation. The average response time due to sample transfer and mixing times is 55 ms, well below the engine cycle period (100 ms) for the considered engine speeds, thus suitable for single-cycle measurements carried out in this work. Utilizing the fast-response capability of the FEN, it is observed that cycle-specific gross indicated mean effective pressure (GIMEP) and [Formula: see text] are negatively correlated ([Formula: see text]: 0.2–0.7), implying that cycles with lower GIMEP emit more soot. The physical causes of this association deserve further investigation, but are expected to be caused by local fuel-air mixing effects. The averaged exhaust-port [Formula: see text] is similar to the diluted gravimetric measurements, but the cycle-to-cycle variations can only be detected with the FEN. The methodology developed here will be used in future investigations to characterize PM emissions during transient engine operation, and to enable exhaust-stream PM measurements for optical engine experiments.


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