scholarly journals Controlling parameters of intake stroke of gas piston engines using the method of small deviations

2020 ◽  
pp. 49-55
Author(s):  
A.G. Klimenko ◽  
Keyword(s):  
Ecological Impact ◽  
Relative Difference ◽  
Combustible Mixture ◽  
Effective Parameters ◽  
Piston Engine ◽  
Small Deviations ◽  
Burning Temperature ◽  
Fuel Burning ◽  
Air Intake ◽  
Intake Stroke

A mathematical model of estimation of thermal and effective parameters of the most important part of cogeneration system of gas piston engine working in cogeneration mode was developed. Parameters of fresh air intake stroke with variable conditions of the environment using the method of small deviations were studied. The advantages of using the method of small deviations are the possibility of linearization of calculation equations as well as making calculations of not absolute but relative parameter change. The main parameters of fresh air intake by a cylinder are parameters of combustible mixture at the end of the intake stroke: combustible mixture pressure pa, the level of compression ε, the level of heating of fresh charge during the intake ΔT, parameters of residue gases (quantity Mr, pressure pr and temperature Tr), temperature of combustible mixture Tк. Using the method of small deviations for estimation of influence of the temperature of combustible mixture on effective values of gas piston engine led to an important finding: relative change of specific effective fuel consumption (economical part of gas piston engine exploitation) is in reverse relation to squared relative difference of temperature of supercharging air. In addition, cooling of supercharging air will positively influence temperatures inside engine cylinders and consequently fuel burning temperature. In turn, lowering the fuel burning temperature will improve ecological impact of the engine and reduce exhaust of harmful components into the atmosphere, in particular NOx.

Investigation on performance and combustion of compression ignition aviation piston engine burning biodiesel and diesel

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rui Liu ◽  
Wanzhong Zhao ◽  
Zhenyu Wang ◽  
Xiaqing Liu
Keyword(s):  
Ignition Delay ◽  
Alternative Fuel ◽  
Combustion Characteristics ◽  
Pilot Injection ◽  
Compression Ignition ◽  
Piston Engine ◽  
Content Type ◽  
Fuel Burning ◽  
Main Injection ◽  
Load Conditions

Purpose This study aims to contrastively investigate the effects of biodiesel and diesel on the power, economy and combustion characteristics of a compression ignition aviation piston engine for unmanned aerial vehicles. Design/methodology/approach Biodiesel used as alternative fuel will not be mixed with diesel during experimental study. Pure diesel fuel is used for the comparative test. Same fuel injection strategies, including pilot and main injection, are guaranteed for two fuels in same test points. Findings The engine-rated power of biodiesel is lower than diesel, which results in higher specific fuel combustion (SFC) and effective thermal efficiency (ETE). Biodiesel has the faster burning rate, shorter combustion duration. The crank angle of 50% mass fraction burned (CA50) is earlier than diesel. The ignition delay angle of biodiesel and diesel in the pilot injection stage is almost the same at high engine speed. As the speed and load decrease, the ignition delay angle of biodiesel in the pilot injection stage is smaller than diesel. At 100% high load conditions, the fuel-burning fraction of biodiesel in the pilot injection is the same as diesel. The peak heat release rate (HRR) of biodiesel is slightly lower than diesel. At 20% part load conditions, the fuel-burning fraction of biodiesel in the pilot injection stage is lower than diesel. Because of the combustion participation of unburned pilot injected fuel, the peak HRR of biodiesel in the main injection is equal to or even higher than diesel. Originality/value The application feasibility of alternative fuel and its effects on aviation engine power, economy and combustion characteristics will be evaluated according to the “drop-in“ requirements and on the low-cost premise without changing the aviation engine structure and parameters.

Compound Diesel Engines for Aircraft

1954 ◽  
Vol 58 (525) ◽  
pp. 613-633 ◽  
Author(s):  
E. E. Chatterton
Keyword(s):  
Gas Turbine ◽  
Diesel Engines ◽  
Piston Engine ◽  
Exhaust Gases ◽  
Air Intake

The association of a gas turbine with a piston engine is by no means a recent conception. As early as 1924 a Napier Lion Series V engine was equipped with a turbine in the manner shown in Fig. 1, the exhaust gases being fed into the turbine to provide all the power to drive the engine supercharger.At a later date during the 1939-1945 War, many engines were installed in operational aircraft fitted with “turbo-chargers” of the type shown in Fig. 2, in which an exhaust activated turbine drives a subsidiary blower boosting the air intake of the normal engine supercharger.

Thermodynamic Simulation and Prototype Testing of a Four-Stroke Free-Piston Engine

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Jiming Lin ◽  
Zhaoping Xu ◽  
Siqin Chang ◽  
Ningxia Yin ◽  
Hao Yan
Keyword(s):  
Thermodynamic Simulation ◽  
Thermodynamic Cycle ◽  
Energy Conversion Efficiency ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Simulation And Experiment ◽  
Intake Stroke ◽  
Engine System ◽  
Insight Into

In order to achieve higher-energy conversion efficiency, a free-piston engine with an improved four-stroke thermodynamic cycle is investigated in this paper. This cycle is optimized according to the variable strokes feature and is characterized by the short intake stroke, the complete expansion stroke, the external pressurization, and the intercooling. The development of a four-stroke free-piston engine system simulation model was described, and the effects of the cycle on the system performances were qualitatively analyzed. According to the experiment of the prototype, the generating efficiency of 33.4% can be achieved when the system is fueled with gasoline and the output power is significantly increased from 1.62 to 2.68 kW. The simulation and experiment results are analyzed in detail, giving insight into the performances of the system. Studies show that the energy-saving and environmental protection performances of the system can be significantly promoted by using the improved thermodynamic cycle.

Combustion Analysis of Twisting-Blade Piston Diesel Engine Fuelled With Karanja Bio-Diesel

2013 ◽  
Author(s):  
Chandrashekarapur Ramachandraih Rajashekar ◽  
Tumkur Krishnamurthy Chandrasekhar ◽  
Tejendra Prasad ◽  
Chelur Rangalppa Kemparaju ◽  
Chebiyyam Uma Shankar
Keyword(s):  
Diesel Engine ◽  
Cone Angle ◽  
High Viscosity ◽  
Combustible Mixture ◽  
Emission Characteristics ◽  
Combustion Analysis ◽  
Piston Engine ◽  
Compression Stroke ◽  
Piston Crown ◽  
Atomization Characteristics

Bio-diesels have very poor atomization characteristics, due to decreased cone angle because of high viscosity and low volatility. Innovativeness is required to use the bio-diesel as efficient vehicular fuel. This paper presents the effect of piston geometry on combustion and emission characteristics of Karanja bio-diesel fuelled C.I.Engine. The piston crown has been modified into twisting blade combustion chamber. Three blades are made to twist through an angle of 60o in the piston crown at the end of compression stroke to induce turbulence to improve the combustibility of combustible mixture. In the present work the combustion and emission characteristics of twisting blade piston fuelled with Karanja bio-diesel have been studied and compared with standard piston engine.

scholarly journals Intake characteristics and pumping loss in the intake stroke of a novel small scale opposed rotary piston engine

2020 ◽  
Vol 261 ◽  
pp. 121180 ◽  
Author(s):  
Jianbing Gao ◽  
Guohong Tian ◽  
Phil Jenner ◽  
Max Burgess
Keyword(s):  
Small Scale ◽  
Piston Engine ◽  
Intake Stroke

Numerical investigation into the fuel evaporation and mixture formation characteristics of a free-piston diesel engine

2019 ◽  
Vol 21 (7) ◽  
pp. 1180-1192
Author(s):  
Chenheng Yuan ◽  
Cuijie Han ◽  
Mian Yang ◽  
Yan Zhang
Keyword(s):  
Combustion Chamber ◽  
Ignition Delay ◽  
Combustion Engine ◽  
Combustible Mixture ◽  
Fuel Spray ◽  
Piston Engine ◽  
Free Piston ◽  
Injection Process ◽  
Free Piston Engine ◽  
Mixing Characteristics

The free-piston engine generator becomes a new-type potential substitute for the conventional crankshaft combustion engine. This article presents a simulation to study the fuel spray and mixing characteristics of a diesel free-piston engine generator by comparing a corresponding crankshaft combustion engine. A full-cycle model which couples with piston dynamics, combustion, and gas exchange is developed to simulate the fuel spray, atomization, and mixing in the free-piston engine generator. The result indicates that compared with the crankshaft combustion engine, the free-piston engine generator provides a higher temperature and pressure for fuel spray and mixing during the ignition delay, but its ignition delay lasts shorter. The free-piston engine generator shows a shorter spray penetration and more fuel impingement due to its smaller combustion chamber volume during the injection process. The free-piston engine generator exhibits a lower level of air utilization and worse uniformity of fuel–air mixture in combustion chamber. In addition, the shorter ignition delay of free-piston engine generator makes the time of atomization, evaporation, and mixing of fuel shorter, and the mixing effect of free-piston engine generator is worse, resulting in less combustible mixture formed during the ignition delay. In addition, some guiding suggestions have been proposed to improve the fuel spray and fuel–air mixing characteristics of free-piston engine generator.

Reductions of Bio-Diesel Exhaust Emissions through Engine Combustion Chamber Design Modifications — An Experimental Study

2014 ◽  
Vol 592-594 ◽  
pp. 1751-1755
Author(s):  
C.R. Rajashekhar ◽  
T.K. Chandrashekar ◽  
C. Umashankar ◽  
R. Harish Kumar
Keyword(s):  
Combustion Chamber ◽  
Automotive Industry ◽  
Exhaust Emissions ◽  
High Viscosity ◽  
Combustible Mixture ◽  
Global Market ◽  
Piston Engine ◽  
Chamber Design ◽  
Engine Combustion ◽  
Automobile Engines

Increased demand and production in all segments of the automotive industry has driven the nation to impose stringent emission norms for automobile engines. At this juncture, bio-diesel has sufficient attraction as vehicular fuel. But the properties of bio-diesels are not the same as diesel fuels, including high viscosity and low volatility. Due to this inherent problem it exhibits poor atomization, which results in incomplete combustion and increased exhaust emissions. This naturally implies that automotive designers have to focus their research more on engine emissions while at the same time not compromising on power development. This has put enormous pressure on automotive industry to design the engine efficiently and economically to compete with the global market. This paper relates the modification of engine combustion chamber design, for inducing turbulence to improve the combustibility of combustible mixture of karanja bio-diesel and to reduce the exhaust emissions. The modification includes the tri-chambered piston and twisting blade pistons. In the present work the emission characteristics of modified piston engine are compared with the standard piston engine. It was observed that the CO and UBHC emissions can be effectively reduced with tri-chambered piston engine.

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading

2020 ◽  
Vol 21 (5) ◽  
pp. 505
Author(s):  
Yousef Ghaderi Dehkordi ◽  
Ali Pourkamali Anaraki ◽  
Amir Reza Shahani
Keyword(s):  
Residual Stress ◽  
Cyclic Loading ◽  
Stress Relaxation ◽  
Stress Amplitude ◽  
Cyclic Plasticity ◽  
Mean Stress ◽  
Effective Parameters ◽  
Perfect Plasticity ◽  
Residual Stress Relaxation ◽  
Aluminum Plates

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.

КОНЦЕПЦІЯ СТВОРЕННЯ СИЛОВОЇ УСТАНОВКИ СІМЕЙСТВА РЕГІОНАЛЬНИХ ПАСАЖИРСЬКИХ ЛІТАКІВ АН-148/АН-158

2019 ◽  
pp. 50-63
Author(s):  
О. Д. Донець ◽  
В. П. Іщук
Keyword(s):  
Power Plant ◽  
Noise Reduction ◽  
Fuel Consumption ◽  
Electronic System ◽  
Electronic Control ◽  
Level Of Automation ◽  
Auxiliary Power ◽  
Power Plant Control ◽  
Technical Status ◽  
Air Intake

The basic results of calculation and research works carried out in the process of creation of power unit of regional passenger airplanes’ family are given. The design features of the propulsion engines and engine of the auxiliary power plant are described. The aforementioned propulsion system includes propulsion engines D-436-148 and engine AI-450-MS of auxiliary power plant. In order to comply with the requirements of Section 4 of the ICAO standard (noise reduction of the aircraft in site), in part of ensuring the noise reduction of engines, when creating the power plant of the An-148/An-158 aircraft family, a single- and double-layer acoustic filler was used in the structure of the engine nacelle and air intake. The use of electronic system for automatic control of propulsion engines such as FADEC and its integration into the digital airborne aircraft complex ensured the operation of engines, included in the power plant provided with high specific fuel consumption, as well as increased the level of automation of the power plant control and monitoring, and ensured aircraft automation landing in ICAO category 3A. In addition, the use of the aforementioned electronic system, allowed to operate the power plant of the aircraft in accordance with technical status. The use of the AI-450-MS auxiliary power plant with an electronic control system such as FADEC, and the drive of the service compressor from a free turbine, eliminated the effect of changes in power and air takeoff, on the deviation of the engine from optimal mode, which also minimized the fuel consumption. The use of fuel metering system TIS-158, allowed to ensure control of its condition and assemblies, without the use of auxiliary devices, built-in control means. In the fire protection system, the use of the electronic control and monitor unit, as well as the use of digital serial code for the exchange of information between the elements of the system and the aircraft systems, has reduced the number of connections, which increased the reliability of the system and reduced its weight characteristics.

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