Effect Of Piston Research Articles

Effect of the micro-textured piston on the performance of a hermetic reciprocating compressor

A hermetic reciprocating compressor is one of the most critical parts for the energy efficiency of a household refrigerator. Piston-cylinder contact in the hermetic compressor accounts for most of the energy loss. The tribological performance of the piston-cylinder pair can be enhanced by introducing micro-texturing on the piston surface. In this research, an experimental study is presented to tribologically assess the effect of the micro-textured piston on the performance of the hermetically sealed reciprocating compressor. The micro-texture on the piston surface was prepared by the laser surface texturing method. Four different micro-textures were studied: radial micro-grooves, axial micro-grooves, mesh micro-grooves, and micro-dimples. The textures’ size, shape, and depth were studied using scanning electron microscopy (SEM) and white light interferometry (WLI) techniques. The results were compared with the non-textured piston compressor. It was found that the radial, axial, and mesh micro-grooves pistons have a negative effect on the coefficient of performance of the hermetic reciprocating compressor. However, the piston with the micro-dimples texture increased the compressor's coefficient of performance by 1%. Refrigerant leakage from the piston-cylinder clearance was also investigated and it was observed that micro-dimples on the piston surface decrease the refrigerant leakage by 35% due to the presence of a continuous oil film between piston and cylinder. The compressor's cooling capacity (Qc) was observed to be increased by 1 W in the case of a micro-dimpled piston.

Transient flow performance and heat transfer characteristic in the cylinder of hydraulic driving piston hydrogen compressor during compression stroke

With the advantages of large flow capacity and high pressure, the use of hydraulic driving piston compressors in hydrogen refueling stations is becoming the development trend. Understanding transient flow and heat transfer characteristic is the key issue for the design and application of hydrogen compressors. The transient model of the hydraulic driving piston compressor is constructed by dynamic mesh and the National Institute of Standards and Technology (NIST) real hydrogen model, which accurately predicts flow field and heat transfer. Moreover, the effect of piston reciprocating cycle frequency on hydrogen parameters variation and heat transfer characteristic is investigated. Adiabatic compression theory is commonly applied in the design of reciprocating compressors. The results show that due to the heat transfer, the exhaust temperature predicted by the adiabatic compression theory is 6.29 K higher than the actual value. This study provides beneficial references for the design optimization and reliable operation of hydraulic driving piston hydrogen compressors.

Experimental study on the effect of the thermal barrier coated (TBC) piston on combustion of gasoline compression ignition (GCI)

Gasoline compression ignition (GCI) has the advantage in achieving high thermal efficiency and low emissions simultaneously. However, the difficulty in realizing stable compression combustion at low load is a major problem that GCI faces and needs to be addressed. In addition, improving thermal efficiency of internal combustion engine is also an important research topic, especially for satisfying low carbon goals in the future. Therefore, to explore strategies to improve combustion stability and thermal efficiency of GCI combustion, the low thermal conductivity ceramics (MgZrO3) was coated on the top surface and combustion chamber of the piston to reduce the thermal conductivity, then achieving the purpose of increasing the in-cylinder temperature and reducing the heat transfer. The experiment was conducted under different loads conditions to investigate the effect of thermal barrier coated (TBC) piston on GCI combustion. The result shows that the indicated thermal efficiency of GCI can be increased by 6.4% with the TBC piston at low load, meanwhile the THC and CO emissions are also reduced effectively. Furthermore, employing TBC piston can significantly improve the combustion stability of low load GCI combustion and therefore has great potential to extend lower load operation. However, the effect of TBC piston on improving indicated thermal efficiency decreases as engine load increases, and the difference in combustion between the TBC piston and piston without TBC is fairly small under high load condition. Compared to piston without TBC, the indicated thermal efficiency of TBC piston is higher and change slightly as EGR rate increases. With the TBC piston, lower NOx and soot emissions can be obtained while the indicated thermal efficiency remains at high value by introducing high EGR rate.

Effect of the balanced piston on the stability of hydraulic pilot-operated relief valve

The stability of a pilot-operated relief valve is investigated through mathematical modeling and experimental measurement. A comprehensive mathematical model of a cartridge-type pilot-operated relief valve is developed, which is designed with a balanced piston at the front of the pilot poppet. The dynamic behavior of such a valve was then investigated using a frequency-domain analysis method. The balanced piston was found to have a marked effect on the stability of the relief valve. The local stability of the valve under various annular clearances was further discussed by the normalization method. The results indicate that an appropriately sized balanced piston can improve the stability of the relief valve’s subsystem. However, when the annular clearance is large, the subsystem’s dynamic characteristics do not change obviously, although it does raise the pilot poppet damping ratio to some extent. Furthermore, numerical simulations and experimental studies were produced to validate the above conclusions, and excellent agreement between the measurement and the model was obtained.

Combustion and emission performance of isopropanol-butanol-ethanol (IBE) mixed with diesel fuel on marine diesel engine with nano YSZ thermal barrier coating

The effect of piston coating on the combustion and emission performance of IBE and diesel blended fuel was experimental studied. The experimental conditions were set to be a orthogonal matrix of three loads from low to high, coated and uncoated, IBE20 fuel and D100 fuel. The heat release rate, ignition delay periods and combustion duration were calculated by the cylinder pressure curves. The break thermal efficiency was calculated by the fuel consumption rate, and the concentration of soot, NOx and CO in the exhaust was collected. It was found that Nano-YSZ thermal barrier coating (TBC) can effectively reduce heat transfer loss, increase in-cylinder combustion temperature, and effectively solve the problems of high latent heat of vaporization and ignition delay of alcohol fuel. The experimental results showed that the Nano-YSZ coating could effectively reduce the brake specific fuel consumption, which was reduced by 5% when using pure diesel under 25% load, and was reduced by 7.3% for IBE20 fuel. Furthermore, TBC_IBE20 (IBE20 used in TBC Engine) exhibited the highest thermal efficiency under the three working conditions. Under all operating conditions, IBE20 had the potential to reduce soot emissions but increase NOx emissions, and thermal barrier coatings could amplify this potential.

Effect of piston and cylinder head swirl generation techniques on the performance of ceiba pentandra and nigella sativa B20 biodiesel blended diesel engine operation

Biodiesels are renewable fuels and their usage in diesel engine can decrease the dependence on fossil-based fuels which are exhaustive in nature. Further they can effectively address the alarming increase in emission levels in the atmosphere and provide savings in the foreign exchange. The present work mainly focuses on the effect of swirl techniques adopted on the performance of the modified diesel engine powered with two B20 based biodiesels derived from Ceiba Pentandra (CPNTOME B20) and Nigella Sativa (NIZSAOME B20) respectively. The swirl techniques are adopted by suitable modifications on both the piston and cylinder head surfaces respectively. Optimized number of cavities on piston and cavities and domes on the cylinder head improved the diesel engine performance powered with selected biodiesel blended fuels. Accordingly, 6 number of cavities on the piston and 2 domes and 3 cavities on the cylinder head surfaces provided higher brake thermal break efficiency (BTE), lower hydrocarbons (HC), carbon monoxide (CO), smoke emissions while nitric oxide (NOx) emissions were increased for the diesel engine powered with two B20 blends compared to other swirl combinations used. Among the two biodiesels used CPNTOME B20 showed higher engine performance compared to NIZSAOME B20. BTE of engine fuelled with diesel increased by 4.86% and 6.54% respectively when compared with B20 blends of CPNTOME and NIZSAOME. Smoke emissions of engine fuelled with diesel decreased by 8.27% and 11.43% respectively when compared with B20 blends of CPNTOME and NIZSAOME.

Experimental studies on the effect of TBC piston in a dual-fueled diesel engine

Oxy-hydrogen gas (HHO) is a carbon-clean alternative fuel like hydrogen and is composed of hydrogen and oxygen in the ratio of 2:1. The significant properties of hydrogen (which is present in HHO) such as high octane rating, better mixing characteristics, high diffusivity, high flame speed also ensure its possible use to run a compression ignition (CI) engine in dual fuel mode. On the other hand, the application of thermal barrier coatings (TBCs) to engine components may reduce thermal fatigue, and the heat loss to the surroundings. In this experimental study, the combined effect of HHO gas on the combustion, performance, and emission characteristics of a dual-fuel diesel engine fitted with two different thermal barrier coated (TBC) pistons was experimentally investigated. Commercially available D2 quality petro-diesel (D100) and a blend composing 20% Jatropha and 80% D100 named as JME20 were used as pilot fuels, while the HHO gas was used as inducted fuel in dual-fuel operation. The experiments were carried out in a single cylinder, four storke, air-cooled, stationary type direct injection (DI) diesel engine fitted with the uncoated and coated pistons were operated in two different dual operations viz., D100 + HHO and Opt.JME20 + HHO. Two separate pistons were used to coat its top crown surface with Yttria-stabilized zirconia (YSZ) and YSZ + CeO2. The results obtained for the combustion, performance, and emission parameters of the dual fuel diesel engine fitted with the TBC piston and run in dual fuel operation of D100 + HHO and Opt.JME20 + HHO were evaluated, analyzed, and compared with those of the baseline data. The results revealed thatthe brake thermal efficiency of Opt.JME20 + HHO run in dual-fuel operation was found to be higher by about 5.9% compared to that of the baseline data at full load, for the YSZ + Cerium-oxide (CeO2) coated piston-fitted engine by minimizing the heat loss to the surroundings. Similarly, the maximum carbon monoxide (CO), unburnt hydrocarbon (HC), and smoke emissions with the YSZ + CeO2 coated piston fitted engine operation in dual fuel mode with Opt.JME20 + HHO was found to be lesser by about 44.1%, 46.7%, and 21.5%, respectively compared to that of the baseline data at full load.

Stainless Steel Thermal Spray Coating of Cylinder Bores for VC-Turbo Engine

<div class="section abstract"><div class="htmlview paragraph">Nissan’s variable compression turbo (VC-Turbo) engine has a multilink mechanism that continuously adjusts the top and bottom dead centers of the piston to change the compression ratio and achieve both fuel economy and high power performance. Increasing the exhaust gas recirculation (EGR) rate is an effective way to further reduce the fuel consumption, although this increases the exhaust gas condensation in the cylinder bores, causing a more corrosive environment. When the EGR rate is increased in a VC-Turbo engine, the combined effect of piston sliding and exhaust gas condensation at the top dead center accelerates the corrosive wear of the thermal spray coating. Stainless steel coating is used to improve the corrosion resistance, but the adhesion strength between the coating and the cylinder bores is reduced. Trial production of the coatings with different linear expansion coefficients was conducted, and the sensitivity of the linear expansion coefficient and adhesion strength was obtained. Consequently, the adhesion strength was found to have a maximum value with respect to the linear expansion coefficient. By contrast, the surface observation of this coating after the honing process showed an increase in surface porosity. The martensitic content in the coating was reduced, and the appropriate martensitic content and chemical composition with the optimal corrosion resistance, adhesion strength, and surface porosity were found. Using this coating (0.01C-12Cr-0.22Ni-0.35Mn), the corrosive wear at the top dead center was resolved. Consequently, the fuel economy was improved by more than 4% compared with that of the current VC-Turbo engine, which has already adopted a carbon-steel-based coating.</div></div>

Study on the effect of piston and piston ring specifications on engine lubricant oil consumption

Study on the effect of piston and piston ring specifications on engine lubricant oil consumption

Enhancing Diesel Engine Performance and Balancing Emissions with Effect and Contribution of MgO-ZrO2 and AT13 Layered Piston

Modern engines need to produce more efficiency in all aspects with low specific fuel consumption and lesser pollutions for environmental betterment. The purpose of this research work is to experimentally identify better thermal barrier coating and their impacts to enhance engine performance with lower specific fuel consumption. Piston crown of a single-cylinder diesel engine is coated with MgO-ZrO2 and Al2O3-13%TiO2 and tested under different loading conditions. The impact of thermal barrier coating performance and emissions compared with standard diesel engine characteristics is investigated. MgO-ZrO2 and Al2O3-13% TiO2 are selected as additional material to coat the piston crown because these materials are physically stable and thermal properties like low heat conductivity, high melting point and high thermal expansion are stable at high temperature. This experimental work has shown an increase in brake thermal efficiency of 32.1% for the TBC engine from 23.4% for the UC engine. Therefore, there is a decrease in brake-specific fuel consumption for TBC engine 0.27 kg/kWh from uncoated engine 0.37 kg/kWh at 9 kg of load decreased by 27.03%. It was observed from the heat balance sheet that the TBC engine useful work was increased by 3.5% compared with the uncoated engine which ultimately decreases the effect of gases like CO and HC due to an increase in the complete combustion by the thermal barrier coating.

Wave generation characteristic analysis of piston and flap type wave maker with rotary-valve-control vibrator

Wave maker is one of the most important experimental equipment in marine engineering. To meet the demands of simulation of higher wave amplitude and compare the effect of piston and flap type wave generation, a new wave generation device was proposed and a new piston and flap type wave maker with a rotary-valve-control vibrator was developed. A mathematical model of the new wave maker was established and analysed by Simulink, and a series of experiments were conducted on the wave maker to analyze wave generation characteristics. The results show that the wave maker can adjust the distance of wave paddle and generate different regular waves. The bigger the axial opening size of the valve port, the larger the wave paddle amplitude and the wave amplitude; the higher the pressure, the higher the wave paddle amplitude and the wave amplitude. High frequency wave making is more efficient than the lower one, and piston type wave making is more efficient than those wave makers that generate waves by flap type.

Study on the effect of piston and piston ring specifications on oil consumption

Study on the effect of piston and piston ring specifications on oil consumption

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ПОРШНЕВОГО ДВИЖЕНИЯ ПОЕЗДОВ МЕТРОПОЛИТЕНА НА ОБЕСПЕЧЕННОСТЬ ВОЗДУХОМ СТАНЦИЙ МЕТРО

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ПОРШНЕВОГО ДВИЖЕНИЯ ПОЕЗДОВ МЕТРОПОЛИТЕНА НА ОБЕСПЕЧЕННОСТЬ ВОЗДУХОМ СТАНЦИЙ МЕТРО

Pooled effect of injection pressure and turbulence inducer piston on performance, combustion, and emission characteristics of a DI diesel engine powered with biodiesel blend

In this study, the effect of injection pressure on combustion, performance, and emission characteristics of a diesel engine powered with turbulence inducer piston was studied. Engine tests were executed using conventional diesel and 20% blend of adelfa biodiesel [A20]. The results acquired from renewable fuel A20 in the conventional engine showed reduction in brake thermal efficiency being the result of poor air fuel mixing characteristics and the higher viscosity of the tested fuel. This prompted further research aiming at the improvement of turbulence for better air fuel mixing by a novel turbulence inducer piston [TIP]. The investigation was carried out to study the combined effect of injection pressure and turbulence inducer piston. Considerable improvement in the emission characteristics like hydrocarbon, carbon monoxide, smoke was acheived as a result of optimised injection pressure. Nevertheless, the nitrogen oxide emissions were slightly higher than those of the conventional unmodified engine. The engine with turbulence inducer piston shows the scope for reducing the major pollution and thus ensures environmental safety.

HYDRAULIC SYSTEM MAINTENANCE

Any problem in a hydraulic system in any hydraulic equipment, while working, may decrease the investment to outweigh the cost of maintenance or reconstruction. The hydraulic cylinder is a main component in the hydraulic systems. In most cases of forced stop, the equipment malfunctions in the hydraulic cylinder and its components. Therefore this study aims to repair the performance of hydraulic cylinder after corrosion and determine the best ways for the reconstruction and maintenance of hydraulic cylinder. Also, to study of the electroplating of internal surface of hydraulic cylinder, which is supposed to raise the economic life of the cylinders and consequently the economic life of machine. The studied factors were:(a) treating the surface of cylinder (before treatment, turning, polishing, chromium electroplating) and measuring the force needed to move the piston in the presence of three kinds of oils ( ISO VG numbers are VG32 ,VG22 and VG10 ) as hydraulic liquids and (b) the effect of piston on the cylinder performance (without pressure ring, with one pressure ring and with two pressure rings) after each treatment on the cylinder surface, to evaluate the effect of the previous factors on the cylinder performance (measured by the specific force needed to move piston).. The final data indicated that electroplating of the inner surface of the hydraulic cylinder resulted in improving the performance of the hydraulic cylinder.

Transient Fluid-Structure Interaction in a Control Valve

Numerical investigation on the interaction of a viscous incompressible fluid with a control valve is conducted by using the finite element method and Newmark approach. Variables including displacement, velocity, and acceleration are presented as a function of time to describe movements of the solid system. The velocity vectors, pressure variations, pressure loss coefficients, and energy losses are displayed to reveal the resulting flow fields. It is observed that the motion of the structural element which becomes a moving boundary had a significant influence on the flow fields. In a periodic inlet flow, the motion of the structural system and the resulting flow fields were almost identical for each cycle after the third cycle. The simulated results presented in this paper provide a good description of the induced flow field in a piping system under the effect of a pulsating piston or a wave.

Plane nonstationary gas flow with a strong discontinuity

The problem of plane, nonstationary gas motion under the effect of a piston in the shape of a dihedral angle moving at constant velocity in the gas is considered. In contrast to one-dimensional motion under the effect of a flat piston, a curvilinear shockwave originates here, and the flow becomes nonisentropic and vortical. This problem is examined herein in a linear formulation when the angle of the piston breakpoint is assumed small. The linear problem reduces to an inhomogeneous Riemann—Hilbert problem whose solution is found explicitly. The problem under consideration adjoins a circle of problems associated with shockwave diffraction and reflection studied by Lighthill [1], Smyrl [2], Ter-Minassiants [3], etc.