Gas Internal Combustion Engines Research Articles

Comparative analysis of different heat transfer models, energy and exergy analysis for hydrogen-enriched internal combustion engine under different operation conditions

The implementation of hydrogen as a fuel in internal combustion engines is widely considered a favorable optimal due to its zero-carbon emissions and high energy content. Heat transfer from engine cylinder walls has a major role on engine combustion, performance and emission characteristics. In this study, heat transfer analysis conducted by different heat transfer models and identify the best model to analyse the energy and exergy analysis of hydrogen enriched internal combustion engine. A series of experiments were conducted on a compressed natural gas internal combustion engine across varying hydrogen fractions, EGR ratios, engine speeds and load conditions to capture in-cylinder pressure data and heat transfer rate. The authors compared six distinct models for heat transfer based on absolute percentage errors of maximum pressure and indicated mean effective pressure. These models systematically incorporated into a quasi-dimensional combustion model (QDCM) on MATLAB for hydrogen-compressed natural gas engine, accounting for diverse operating conditions. Convective heat transfer models, including Woschni, Nusselt, Hohenberg, Han, Eichelberg, and Assanis correlations were employed. Comparative analyses were undertaken to identify the most precise correlation for predicting engine in-cylinder pressure and heat transfer rates with experimental results across a broad spectrum of operational conditions. The Woschni model, as presented, is most suitable for the QDCM of the hydrogen-compressed natural gas fuel blend. This suitability is indicated by the close alignment of Taylor length and turbulent intensity coefficients to 1, as well as the minimal absolute percentage error observed for indicated mean effective pressure. It is also observed that heat transfer rate is increased by increasing the engine load 25 %, 50 %, 75 % and 100 % as 49.57 J/deg, 129.26 J/deg, 245.35 J/deg and 250.62 J/deg respectively and heat transfer rate is decreased by increasing the speed of engine 1100 rpm, 1200 rpm, 1500 rpm and 1700 rpm as 137.34 J/deg, 134.21 J/deg, 95.33 J/deg and 48.57 J/deg respectively. The energy and exergy analyses revealed that elevating the engine load corresponds to a reduction in exergy destruction. Brake energy increased 15 % by increasing the load conditions from 25 % to 100 % and decreased 7 % by increasing the speed from 1100 rpm to 1700 rpm. Another significant finding from this study is that the values of both energy and exergy efficiencies were 38.42 % and 40.12 % respectively obtained by thermodynamic analyses.

Повышение энергетической эффективности газопоршневой ТЭС за счет комплексного использования тепловых вторичных энергоресурсов

Recently, the advantages and prospects to use piston gas internal combustion engines for the combined generation of electrical and thermal energy have become increasingly obvious. The range of single capacities of gas piston units (GPU) ranges from 0,1 MW to tens of MW, which makes them more attractive when designing various power facilities. Most brands of gas piston units can operate in co-generation mode, that is, as a combined heat and power plant that simultaneously generates electrical and thermal energy. The purpose of this study is to substantiate the possibility of integrated use of heat of the cooling systems of the gas piston engine of a thermal power plant (TPP). The studies conducted are carried out using well-known methods of thermodynamic calculation of the internal combustion engine cycle, of determination of the components of its thermal balance and thermal calculation of the equipment for utilization of secondary thermal energy resources. The results of the analysis of the heat losses of the GPU drive engine have showed that the total losses during its operation are about 11544,5 kW. Average potential heat losses with flue gases are 45,87 %, and low-potential heat losses with water in cooling systems and oil in lubrication systems are 53,14 %. A schematic diagram is proposed for the integrated utilization of thermal renewable energy resources (RES) at a gas piston thermal power plant. The main difference between the proposed scheme and the existing technical solutions is the utilization of the heat of the low-temperature charge air cooling system after the second section of the compressor and the heat of the engine lubrication system. An analysis of the expenditure part of the energy balance of the drive engine in case of the integrated use of thermal RES in the GPU cycle, has showed that the implementation of energy-saving measures will make it possible to usefully use up to 93,05 % of the supplied energy in the generation of electrical and thermal power.

Elevated temperature tribological assessment of Ni-based cermet self-lubricating coatings deposited by cold spray

Solid lubricant coatings provide reduced friction and wear resistance and hence finding widespread application in harsh environmental conditions, such as gas turbine, aircraft, and internal combustion engines. It is apparent that single lubricant fails to offer effective lubrication over wide temperature range. Hence, two or more solid lubricants are mutually incorporated to achieve the appropriate lubrication by their synergy under harsh service conditions. The current investigation is being carried out to evaluate the synergistic impact of different solid lubricants viz. silver (Ag), molybdenum disulfide (MoS2), hexagonal boron nitride (h-BN) and chromium oxide (Cr2O3) on the frictional properties of coatings from room temperature (RT) to 800 °C. Cold spraying process has gathered extensive acceptance for the development of metallic and metallic-ceramic coatings. The current study elucidated the tribological characteristics of cold sprayed nickel-based high temperature lubrication coatings, namely, Ni-Al-MoS2-Ag (NB0), Ni-Al-MoS2-Ag-5 wt% h-BN (NB5), Ni-Al-MoS2-Ag-7.5 wt% h-BN (NB7.5), Ni-Al-MoS2-Ag-10 wt% h-BN (NB10) and Ni-Al-MoS2-Ag-Cr2O3–7.5 wt% h-BN (NB7.5 + 7 wt% Cr2O3) against Al2O3 ball in an operative testing regime from (RT-800 °C) using ball-on-disc tribometer. Results indicated that NB7.5+ 7 wt% Cr2O3 coating exhibited remarkable self-lubricating and wear resistance properties as compared to other coatings. However, NB7.5+ 7 wt% Cr2O3 revealed slightly higher coefficient of friction (COF) in compare to NB7.5 coating till 400 °C, and beyond that it showed a decreasing trend and lesser COF in compare to other coatings. The observed wear mechanisms at different temperatures were discussed in detail after analyzing the morphologies of worn surface. The pivotal role played by the participating solid lubricants were also discussed in detail which help in to provide the continuous compacted layers at the worn surfaces at elevated temperature.

Исследование процесса впуска в газовых двигателях с внешним смесеобразованием

Purpose: To identify existing problems, namely the low homogeneity of the air-fuel mixture and fuel losses when valves are closed, and the advantages of central fuel injection, namely its relative ease of adjustment and location of gas injectors, and its main differences from distributed injection. To show existing ways to solve these problems. To demonstrate the lack of environmental and economic efficiency in central fuel injection. To calculate the amount of fuel entering the engine exhaust system when the valves are closed. To show ways to increase the efficiency of fuel utilization during engine operation. Methods: Calculation of the mass of natural gas entering the engine exhaust system during the valve overlap period, considering the duration of the period, the cross-sectional area of the valve gap, the total amount of fuel supplied during the intake stroke, the density of the fuel, the flow rate when entering the cylinder and the stoichiometric ratio. Results: The need to consider the amount of fuel consumed when operating a gas engine is shown. The existing problems of using central fuel supply are indicated. A method for calculating gas fuel losses when valves are closed is formulated and justified. It has been established which parameters influence the mass of fuel that does not enter the cylinder during the intake process. It is concluded that it is necessary to use other injection methods, or to significantly improve the intake process of central injection. Practical significance: The influence of the method of supplying fuel to a gas internal combustion engine on the environmental friendliness of the engine and fuel efficiency is shown. A method has been formulated for calculating gas fuel losses during the period of valve overlap, considering the design parameters of the intake system and the duration of opening of the intake valves.

Comparative energy performance analysis of micro gas turbine and internal combustion engine in a cogeneration plant based on biomass gasification

With a view to replacing fossil fuels, biomass electricity generation worldwide has grown from 509 TWh in 2015 to 685 TWh in 2021 and an upward trend is expected for the next years. It is about dispatchable, low-emission power to complement generation from variable renewables. Although modern bioenergy is considered a stable and carbon-neutral source, there is a need to boost the efficiency of the Biomass-to-Energy (BtE) conversion technologies. Accordingly, in this modeling study, attention was drawn to biomass gasification for heat and power, with a special focus on the prime mover characterization for distributed generation. An internal combustion engine (ICE) and a micro gas turbine (mGT), having the same nominal capacity of about 240 kWel when fueled by natural gas (NG), were inserted into a two-way biomass gasification chain and hence fed by clean syngas deriving from a downdraft gasifier. Simulations of the main components of the thermal power plant (gasifier, syngas cleanup, power island) were validated against data available in the published literature and in technical sheets, for specific operating conditions. The next step was to evaluate the overall performance of the entire BtE chain in terms of electrical, thermal, and total efficiency, both at full and part load, in order to highlight the pros and cons of each generator, in a twofold perspective. The last goal was to simulate a load following strategy, for two typical cold and hot days. The results of the thermodynamic analysis indicate that ICE is better performing than mGT, in the simulated context where the power demand from the grid ranges from 80 kWel to 190 kWel, with an ambient temperature between 2 and 35 °C. ICE provides the best performance in CHP mode, with a total efficiency of 62–69%.

Statistical investigation of combustion and emission characteristics of biofuels according to their physical properties: A way to explore suitable alternative fuels

The Pollutant emissions and limited fossil fuel resources attracted researchers toward alternative fuels. Therefore, the combustion of liquid biofuels (as an alternative fuel) is gaining importance in research for the power generation sector for gas turbine engines and internal combustion engines. The physical properties of these fuels play an important role in the combustion characteristics (in terms of flame characteristics, emission characteristics, and flame temperature profile characteristics), and their experimental testing is costly. Considering the importance of research and cost in the experiment, the analysis is carried out to develop a new model for evaluating post-combustion emission characteristics based on the physical properties of liquid fuels. Raw data is extracted from experimental investigations to establish the present analysis models. Experimental studies have been carried out to evaluate the properties of different fuels and their composition-wise effects on flame, temperature, and emission characteristics. Thereby, reliable combustion performance and low emission profiles (in terms of physical fuel properties) can be ensured for potential alternative fuels. The results of the analysis show that specific properties such as high viscosity, high density, and high aromatic content of the fuel have the potential to generate high CO. In contrast, a decrease in these properties promotes high CO2 formation. In addition, low NOx emissions and low CO trends are unlikely to be achieved by simultaneously changing the value of fuel properties. The analysis shows that the low viscosity of the fuel induces low soot emission and flame length retardant.

Research of the efficiency of gas ice’s under various load modes

When changing the load modes of gas internal combustion engines, the efficiency and economy of operation of such engines change significantly. The article discusses five main modes of operation of a gas internal combustion engine: start-up mode, idle mode, average (optimal) stroke mode, maximum (full) stroke mode, high speed mode (acceleration, acceleration). The article also discusses the parameters of the internal combustion engine: coefficient of performance, specific fuel consumption, excess air coefficient, degree of severity. Keywords: start mode, idle mode, medium mode, full flow mode, extreme conditions mode, excess air coefficient

SPRAY CHARACTERISTICS AND ENERGY ANALYSIS OF N-HEPTANE ATOMIZATION BY HEATED AIR IN A MINI AIR-BLAST ATOMIZER

Liquid fuel atomization plays an important role in fuel combustion of gas turbine engines and internal combustion engines. To reveal the interaction of atomizing air temperature (AAT) and air-liquid mass ratio (ALR) during the air-blast atomization process, <i>n</i>-heptane atomization in an air-blast atomizer is carried out experimentally at AAT = 300 K-450 K and ALR = 0.9-2.9. The spray cone angle (φ) presents a three-stage featured with rising ALR and enters the stable stage of 25°-26°. ALR played a decisive role in droplet size and velocity, while the AAT effect is ancillary and has a notable performance at part of conditions. The AAT effect on droplet size is more obvious at low ALR, while the effect on droplet velocity is strengthened as ALR increases. The same conclusion is also obtained in the analyses of droplets kinetic energy and surface energy. This discovery inspires us to increase AAT to compensate for the atomization performance decrease caused by reducing ALR. It can reduce the air pump load while stabilizing the atomization performance for large air mass flow condition. Even at low liquid mass, increasing AAT yields a visible improvement.

Commercial Fleet Vehicle Additions and Replacements and the Potential Market Penetration for Electric Vehicles

Commercial fleets can play a major role in the rapid evolution of plugin hybrid electric vehicles (PHEV) and battery electric vehicles (BEV) market penetration. Using survey data in this analysis we identify groups of commercial fleets based on the attributes of the next vehicle planned to be added to a fleet and the propensity of replacing a current vehicle with an electric vehicle. We first develop principal components representing dimensions of the desired vehicle characteristics (price, efficiency, size and fuel type, timing of vehicle procurement, replacement of current vehicle or addition to the fleet, and intended purchase of new, used, or leased). Using 8 principal components capturing approximately 91.55% of the variance in the variables listed above and hierarchical clustering we derive six distinct market segments. One segment contains 43.5% of the total responses preferring a PHEV to replace a current vehicle in the fleet, it is a segment that is composed of 100% PHEV preferring respondents and almost all of them expect to purchase a small vehicle and 92% will do that within 5 years. The average price they expect to pay is approximately $27,000 and the expected efficiency to be about 55 miles per gallon equivalent (MPGe). Another segment contains 91.0% BEV preferring respondents who are only 11.6% of the sample. This segment also prefers small vehicles to replace vehicles in their fleet, possibly leasing and expecting to pay approximately $46,800 with an efficiency of about 100 MPGe. The other four segments are dominated by gasoline, diesel, and natural gas internal combustion engine vehicles.

Features of Gas Flow in the Axial Stage of a Turbine with an Adjustable Nozzle Vane Assembly

The method of changing the gas flow rate through the turbine by adjusting (turning) the nozzle vanes has been known as the most economical one for more than 50 years. It is most widely used in transport gas turbines and internal combustion engine pressurization units. Recently, many articles have appeared in the technical literature on the advisability of using adjustable nozzle vane assemblies (ANVA) in advanced aircraft engines, power generating units, and in turbo-expander units of natural gas preparation and low-temperature separation systems. In all cases of using ANVAs, their developers are attracted by the possibility of economical and reliable provision of variable operating modes of installations. The article shows by calculation that a decrease in the stage efficiency due to the presence of end gaps in the ANVA, related to the flow-over the nozzle vane ends on the profile pressure side to the suction side and subsequent interaction with the main flow through the interblade channel, can be so significant, especially with low-height vanes, that it can lead to vanishing the advantages of this flowrate changing method. Design measures for tightening the gaps in the form of peripheral and root cylindrical bosses at the profile ends, which eliminate overflows in the vane end major part and partially screening the gap are proposed and studied. A favorable effect of the proposed measures on the losses in the ANVA and in the turbine stage has been confirmed.

Effects of low-grade gas composition on the energy/exergy performance of a polygeneration system (CH 2 HP) based on biomass gasification and ICE

Bio-hydrogen from sustainable biomass (i.e. agro-industrial residues) gasification can play a relevant role in the hydrogen economy, providing constant hydrogen from renewable sources. Nowadays, most hydrogen production systems integrate one or more water-gas shift (WGS) units to maximize the hydrogen yield that, however, needs additional syngas treatments, investment and operational costs. Besides, different electricity inputs are needed along the process to power the compression of raw syngas, shifted syngas, and pure hydrogen to the desired pressure. This common process integration with WGS generates a kind of off-gas from the hydrogen separation unit whose composition may or may not be suitable for power production, depending on the operating conditions of the gasification unit. In this regard, this work proposes a different approach in which no WGS reactors are involved and the off-gas is used to generate heat and power to provide the energy input needed by the system. In particular, the authors tested the bio-syngas and the corresponding off-gas in a 4-cylinders, spark ignition natural gas internal combustion engine operated in cogeneration mode with the aim to analyse the effect of removing the hydrogen from the original bio-syngas on mechanical/electric and thermal power, on fuel efficiency and CO2 specific emission.

Experimental characterization of spark ignited ammonia combustion under elevated oxygen concentrations

Due to its nature as a carbon free fuel and carrying hydrogen energy ammonia has received a lot of attention recently to be used as an alternative to fossil fuel in gas turbine and internal combustion engines. However, several barriers such as long ignition delay, slow flame speed, and low reactivity need to be overcome before its practical applications in engines. One potential approach to improve the ignition can be achieved by using oxygen enriched combustion. In this study, oxygen-enriched combustion of ammonia is tested in a constant volume combustion chamber to understand its combustion characteristics like flame velocity and heat release rates. With the help of high speed Schlieren imaging, an ammonia-oxygen flame is studied inside the combustion chamber. The influence of a wide range of oxygen concentrations from 15 to 40% are tested along with equivalence ratios ranging from 0.9 to 1.15. Ammonia when ignited at an oxygen concentration of 40% with an equivalence ratio of ϕ= 1.1 at 10 bar has a maximum flame velocity of 112.7 cm/s. Reduced oxygen concentration also negatively affects the flame velocity, introducing instabilities and causing the flame to develop asymmetrically due to buoyancy effects inside the combustion chamber. Heat release rate (HRR) curves show that increasing the oxygen concentration from 21 to 35% of the mixture can help reduce the ignition delays. Peak HRR data shows increased sensitivity to air fuel ratios with increased oxygen concentrations in the ambient gas. HRR also shows an overall positive dependence on the oxygen concentration in the ambient gas.

Methane slip reduction of conventional dual-fuel natural gas diesel engine using direct fuel injection management and alternative combustion modes

Alternative combustion mode and change of spray geometry show potential for methane slip reduction in a dual fuel diesel-natural gas internal combustion engine. Three combustion regimes are simulated; a conventional diesel methane dual-fuel combustion and two modes of reactivity controlled compression ignition (RCCI) with early (EIRCCI) and late (LIRCCI) injections. Methane is injected as the premixed fuel into the port and diesel as direct-injected fuel in all combustion modes. The start of direct fuel injection (SOI) is used as the combustion management tool, swiping from misfiring to knock limits at part loads.By switching combustion mode from conventional (CDF) to LIRCCI and EIRCCI, methane slip is reduced by 12% and 33%, respectively. SOI is used effectively to manage methane slip in any combustion mode, but the effect is more substantial in the EIRCCI mode.Emission results support methane slip trends’ observations. Nitrogen oxides (NOx) emission is increased in CDF by advancing SOI and decreased in both the LIRCCI and EIRCCI modes. Compared to CDF, late and early injection RCCI modes produce 417% and 67% more soot. Also, results show that high levels of methane slip in CDF can be reduced to some extent without any geometry modification by SOI management.Three diesel spray angles (SAs) of 60, 90, 120° are examined. Minimum methane slip is obtained when the SA is towards the squish area, and maximum methane slip is obtained when the SA is towards the piston bowl. Increasing SA from 60 to 90 and 120° results in a 16.4% and 42.5% reduction of methane slip.

Laminar flame speed of methane/air stratified flames under elevated temperature and pressure

Flame propagation under mixture stratification is relevant to a wide range of applications including gas turbine combustors and internal combustion engines. One of the local stratification effects is known as the back-support effect, where the laminar flame speed is modified when a premixed flame propagates into gradually richer or leaner mixtures. A majority of previous studies have focused on the propagation of methane/air stratified flames under standard temperature and pressure. However, stratified combustion often occurs under elevated temperature and pressure in practical applications, which may influence the characteristics of the back support effect through modified reaction pathways. This study performs numerical simulations of stratified laminar counterflow flames under an Atmospheric Temperature and Pressure (ATP) condition and an Elevated Temperature and Pressure (ETP) condition and examines the influence of elevated temperature and pressure on the back-support effect. Reaction flow analyses were extensively conducted to elucidate the difference in the primary reaction pathway between the two conditions. When scaled by the stratification Damköhler number, the back-support effect on the rich-to-lean stratified flame is weaker under the ETP condition than the ATP condition in the stoichiometric to lean region. This is due to increased contribution from reactions involved with OH radicals under the ETP condition, which leads to lower H2 reproduction in the reaction zone than under the ATP condition. The contribution from OH radicals is increased under the ETP condition because the conversion of H into OH is enhanced. These results suggest that the back-support effect may become negligibly small in practical combustors operating under elevated temperature and pressure due to (1) the flame being less sensitive to stratification because of the thinner flame, and (2) the lower H2 reproduction that deteriorates the radical production that drives the back-support effect.

Математичне моделювання процесів в дизель-газотурбінних енергетичних комплексах з термохімічною обробкою палива

This paper discussed the methodological aspects of the study using methods of mathematical modeling of processes in ship power plants with thermochemical fuel treatment. The results of the study of physical and chemical processes in structural and functional blocks, simulating individual links of the thermodynamic cycle, are considered. The combination of blocks with links in the form of material and energy flows makes it possible to model the complete scheme of the mathematical model of the power module. Due to the diversity and complexity of the processes in the combined diesel-gas turbine power complex with a thermochemical fuel treatment system, when modeling, the characteristics of the power equipment were determined separately, followed by merging the results obtained and combining the models with links in the form of material and energy flows. Mathematical models of a gas turbine engine, a recycling circuit, a thermochemical fuel treatment unit were created using the Aspen Plus physical and chemical processes modeling system. Working processes in the internal combustion engine were modeled using the CHEMKIN software package. It has been proven that the universal mathematical models of heat engines, which are part of the power module with thermochemical fuel treatment, require adjustment of the selected basic characteristics. Therefore, mathematical models of structural-functional blocks and groups of blocks contain algorithms for setting up models when they are verified by objective functions. The proposed algorithms provide verification of the developed mathematical models in terms of existing or prospective gas turbine engines and internal combustion engines. These algorithms provide the possibility of correct adjustment of the equipment parameters of diesel-gas turbine power complexes with thermochemical fuel treatment. The mathematical model of the internal combustion engine operating cycle based on the CHEMKIN software package provides an opportunity to conduct a primary assessment of the efficiency of energy conversion in the working cylinder. The results of evaluating the adequacy of the mathematical model of the ICE operating cycle based on the CHEMKIN software package showed a satisfactory agreement between the obtained results and experimental data. The maximum root-mean-square error of the calculated data obtained on the basis of the model is within 8.5%.

Energy and economic analysis feasibility of CO2capture on a natural gas internal combustion engine

AbstractCO2capture by amine scrubbing is a widely developed technology in its most advanced stage of evolution. However, it has never been used to capture CO2from mobile sources. The present study performs an energy and economic analysis of an amine scrubbing CO2capture storage (CCS) system, which takes for the amine regeneration process the waste heat from the exhaust gases of a turbocharged natural gas internal combustion engine (mobile source). The selected engine for the study is an M936G, widely used in freight and passenger transport. A primary and a tertiary amine were chosen for the simulations. In order to reduce volume and increase autonomy, captured CO2is stored as a liquid, therefore, a specific installation is planned. The system is hybridised with an organic rankine cycle (ORC) to reduce the energy penalty on the CCS system. Results show that a CCS system operating with Monoethanolamine (MEA) at 30 wt% achieved a maximum CO2capture rate of 66%, with a penalty over the power engine of only 10%. On the other hand, the economic analysis showed that the CCS system with MEA and without ORC is 31.8% cheaper than a hydrogen fuel cells bus and 26% cheaper than a battery‐electric bus. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

Review of Gas Engine Heat Pumps

In this paper the most promising developments of technology for gas engine-driven heat pumps for the last 15 years are presented. The purpose is to present the latest research studies and changes in this type of device, as well as to help readers to search for publications containing relevant aspects of gas engine heat pumps. Gas engine-driven heat pumps are devices for parallel heating and cooling production based on compressor heat pump technology. However, unlike heat pumps with compressors powered by electric motors, gas engine-driven heat pumps are driven by gas internal combustion engines. The reviewed solutions are an interesting alternative to traditional heating systems, characterized by the higher than 1.0 Performance Energy Ratio which expresses the degree of conversion of the energy contained in the fuel supplied to the device into energy transported to the utility needs. Presented in this review, papers show different solutions for conversion of the energy contained in the fuel into mechanical and thermal energy, and mechanical energy through the shaft system is used to drive the compressor of the heat pump. The presented study shows that, due to the complexity of the system and the wide range of applications, the technology has been subjected to detailed analyses and optimizations during the last 30 years in order to increase the efficiency of devices.

A hybrid-electric propulsion system for an unmanned aerial vehicle based on proton exchange membrane fuel cell, battery, and electric motor

ABSTRACT Most Unmanned Aerial Vehicles (UAV) currently use propulsion systems based on gas turbines or internal combustion engines. However, such systems cannot be used in all sizes of UAVs. To perform a high- endurance mission, a UAV must have an efficient propulsion system and aerodynamic. On the other hand, batteries have a low energy density, which therefore increases the UAV’s weight and imposes penalties on the system. Using fuel cells as the main source of power generation in the UAV propulsion system can increase flight endurance and have reasonable fuel consumption. The aim of the present work is introduce and investigate of a new electric propulsion system based on electric motor, proton exchange membrane fuel cell (PEMFC) and battery for a small UAV. Two different battery discharge strategies are compared for propulsion system design. In addition, static optimization is applied to determine the appropriate size of the various components of the propulsion system. It was found that, the required power at the theoretical endurance speed is about 42.13% lower than that at the actual endurance speed. In addition, the required hydrogen rate and PEMFC area to provide the required power in the proposed hybrid propulsion system are 55.7 g/h and 0.09 m2, respectively. Moreover, the payload weight (with lithium-ion polymer battery) for two battery discharge strategies was 0.71 and 1 kg, respectively. The sensitivity analysis is also used to determine the parameters affecting the final performance of the propulsion system.

Hydrogen energy pilot introduction – Technology competition

Hydrogen energy technologies are considered as the cutting-edge clean energy technologies all over the world. Novel concept of hydrogen energy development in Russia, proposed by Government has hydrogen technologies equipment development, production and introduction into domestic market as one of the tasks. Foreign experience shows that governmental support is very important for successful branch development. Waste hydrogen from chlorine industry utilization can be energy-efficient and attractive niche for fuel cells and hydrogen-fuelled heat engines application. Lifetime and capital costs are important parameters for technology choice decision. Energy cost and hydrogen consumption comparison were carried out for gas microturbines (MGT), fuel cells (FC) and internal combustion engines (ICE) in this paper. Analysis showed polymer electrolyte membrane fuel cells and gas microturbines to be the most promising technology in this niche while for internal combustion engines lifetime is an issue. Solid oxide fuel cells need significant capital costs decrease for successful market introduction. Solid oxide fuel cells, MGT and ICE have also additional advantage for Russian conditions due to high-potential heat production possibility. • Сhlorine industry waste hydrogen utilization is considered as the prospective niche for hydrogen energy pilot introduction. • Lifetime and capital costs are the main parameters influencing different hydrogen utilization techniques economic efficiency. • Polymer electrolyte membrane fuel cells became the most attractive technology due to price decrease during last decade. • Gas microturbines and internal combustion engines also can be considered in case of need in heat energy.

A Review of Using Natural Gas in Internal Combustion Engines

Due to its increasing emissions from combustion of fuels in the internal combustion engines and increasing world concern on global warming problem. It’s a significant issue to use alternative fuels that would be safe for people and the environment. In this article, the previous research's concern on using natural gas is discussed. This research presents the precious studies on the benefits of using natural gas fuel in spark ignition, diesel, and agricultural engines. In addition to modeling focusing on engine parts loads to identify fuel-burning influence. Also presents a former discipline on using hydrogen enrichment to improve fuel efficiency and shows characteristics of using dual fuel in internal combustion engines. The difference between lean combustion and exhaust gas recirculation strategies and produces a comparison between natural gas/methanol and natural gas/gasoline in a dual-fuel engine are reviewed. In addition the comparative study between gasoline and natural gas with a direct injection strategy is presented. Also, this article focus on using natural gas as a fuel with reactive controlled compression ignition (RCCI). It can concluded that using the natural gas fuel is one of the perfect solutions to reduce hydrocarbons emissions and increase the thermal efficiency of fuel combustion and reduce the cost of energy production.