Piston Cylinder Research Articles

Optimisation of various thermodynamic parameters for minimum temperature gradient along cylinder liner

In a piston cylinder assembly, high temperatures are found in cylinder combustion spaces and the cylinder temperature is maintained by the water flowing through the engine jacket. Heat transfer takes place from in-cylinder gases to liner, from the liner to the coolant in the jacket. Generally, the water is treated as the most effective coolant, but the boiling point is raised by the coolant which is glycol based. It also gives lubrication to the pump seal, reduces the liner deterioration/wear and inhibits/avoids freezing. In the current research, different coolant mixture fractions at different flow rates, at various crank angles, are investigated for the control of the cooling rate which subsequently reduces liner distortion. The three-dimensional computational fluid dynamic (CFD) simulation is done here. Here the conjugate heat transfer analysis is used to investigate the heat transfer rate during the cooling in jacket of the engine by means of CFD. The CFD simulation results were certified/confirmed by laboratory tests performed in similar conditions.

The Investigation into the Tribological Impact of Alternative Fuels on Engines Based on Acoustic Emission

The wide use of different alternative fuels (AL) has led to challenges to the internal combustion (IC) engine tribology. To avoid any unpredicted damages to lubrication joints by using AL fuels, this study aims to accurately evaluate the influences of alternative fuels on the tribological behavior of IC engines. Recent achievements of the acoustic emission (AE) mechanism in sliding friction provide an opportunity to explain the tribological AE responses on engines. The asperity–asperity–collision (AAC) and fluid–asperity–shearing (FAS) mechanisms were applied to explain the AE responses from the piston ring and cylinder liner system. A new adaptive threshold–wavelet packets transform (WPT) method was developed to extract tribological AE features. Experimental tests were conducted by fueling three fuels: pure diesel (PD), biodiesel (BD), and Fischer–Tropsch (F–T) diesel. The FAS–AE indicators of biodiesel and F–T diesel show a tiny difference compared to the baseline diesel using two types of lubricants. Biodiesel produces more AAC impacts with higher AAC–AE responses than F–T diesel, which occurs at high speeds due to high temperatures and more particles after combustion than diesel. This new algorithm demonstrated the high performance of using AE signals in monitoring the tribological impacts of alternative fuels on engines.

ТЕОРЕТИЧЕСКОЕ ОБОСНОВАНИЕ ОЦЕНКИ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ ПО ВЕЛИЧИНЕ СУММАРНОЙ ЭДС В ПАРАХ ТРЕНИЯ

The research was carried out in order to determine the possibility of assessing the technical condition of an internal combustion engine (ICE) by the value of the total electromotive force (EMF) that occurs in its friction pairs. The contact area of the rubbing parts and the gap between them affects the electrical resistance in contact, and, accordingly, the value of the resulting EMF according to the established dependence. To confirm the theoretical results, studies were carried out on the UMP-417 engine using a developed measuring complex and a manufactured current-collecting device mounted on the output end of the engine crankshaft. With the operating mode corresponding to the speed of the crankshaft 800 min-1, the total value of the EMF in the measurement circuit cylinder liner-engine block-crankshaft-current collector (TSU) was 83...95 mV. At the same time, in the piston–cylinder liner friction pair, it was equal to 37 ... 47 mV, and in the crank mechanism friction pairs - 46...48 mV. The correspondence of the results of the theoretical calculation and bench studies of the values of the EMF value for a real internal combustion engine was: when measured using the Fluke device for the friction unit of the cylinder liner-piston – 62.1 %, for the friction units of the crank mechanism (root neck-connecting rod, connecting rod neck-connecting rod, root neck-engine block) - 15.1 %. When measured by the V1net device, for the cylinder liner – piston friction unit-85.5 %, for the crank mechanism friction units (root neck-connecting rod, connecting rod neck-connecting rod, root necks-engine block) - 93.2 %. The proposed method for determining the state of the engine by the value that occurs in its EMF friction nodes can be used in the technical diagnostics of engines

Ni-in-garnet geothermometry in mantle rocks: a high pressure experimental recalibration between 1100 and 1325\xa0\xb0C

The temperature-dependent exchange of Ni and Mg between garnet and olivine in mantle peridotite is an important geothermometer for determining temperature variations in the upper mantle and the diamond potential of kimberlites. Existing calibrations of the Ni-in-garnet geothermometer show considerable differences in estimated temperature above and below 1100 °C hindering its confident application. In this study, we present the results from new synthesis experiments conducted on a piston cylinder apparatus at 2.25–4.5 GPa and 1100–1325 °C. Our experimental approach was to equilibrate a Ni-free Cr-pyrope-rich garnet starting mixture made from sintered oxides with natural olivine capsules (Niolv ≅ 3000 ppm) to produce an experimental charge comprised entirely of peridotitic pyrope garnet with trace abundances of Ni (10–100 s of ppm). Experimental runs products were analysed by wave-length dispersive electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We use the partition coefficient for the distribution of Ni between our garnet experimental charge and the olivine capsule left( {{text{lnD}}_{{{text{grt}}/{text{olv}}}}^{{{text{Ni}}}} ; frac{{{text{Ni}}_{{{text{grt}}}} }}{{{text{Ni}}_{{{text{olv}}}} }}} right), the Ca mole fraction in garnet ({mathrm{X}}_{mathrm{grt}}^{mathrm{Ca}}; Ca/(Ca + Fe + Mg)), and the Cr mole fraction in garnet ({mathrm{X}}_{mathrm{grt}}^{mathrm{Cr}}; Cr/(Cr + Al)) to develop a new formulation of the Ni-in-garnet geothermometer that performs more reliably on experimental and natural datasets than existing calibrations. Our updated Ni-in-garnet geothermometer is defined here as:T left(^circ{rm C} right)=frac{-8254.568}{left(left( {mathrm{X}}_{mathrm{grt}}^{mathrm{Ca}} times 3.023 right)+left({mathrm{X}}_{mathrm{grt}}^{mathrm{Cr}} times 2.307 right)+left({mathrm{lnD}}_{frac{mathrm{grt}}{mathrm{olv}}}^{mathrm{Ni}} - 2.639 right)right)}-273pm 55where {mathrm{D}}_{mathrm{grt}/mathrm{olv}}^{mathrm{Ni}}= frac{{mathrm{Ni}}_{mathrm{grt}}}{{mathrm{Ni}}_{mathrm{olv}}}, Ni is in ppm, {mathrm{X}}_{mathrm{grt}}^{mathrm{Ca}} = Ca/(Ca + Fe + Mg) in garnet, and {mathrm{X}}_{mathrm{grt}}^{mathrm{Cr}}= Cr/(Cr + Al) in garnet. Our updated Ni-in-garnet geothermometer can be applied to garnet peridotite xenoliths or monomineralic garnet xenocrysts derived from disaggregation of a peridotite source. Our calibration can be used as a single grain geothermometer by assuming an average mantle olivine Ni concentration of 3000 ppm. To maximise the reliability of temperature estimates made from our Ni-in-garnet geothermometer, we provide users with a data quality protocol method which can be applied to all garnet EPMA and LA-ICP-MS analyses prior to Ni-in-garnet geothermometry. The temperature uncertainty of our updated calibration has been rigorously propagated by incorporating all analytical and experimental uncertainties. We have found that our Ni-in-garnet temperature estimates have a maximum associated uncertainty of ± 55 °C. The improved performance of our updated calibration is demonstrated through its application to previously published experimental datasets and on natural, well-characterised garnet peridotite xenoliths from a variety of published datasets, including the diamondiferous Diavik and Ekati kimberlite pipes from the Lac de Gras kimberlite field, Canada. Our new calibration better aligns temperature estimates using the Ni-in-garnet geothermometer with those estimated by the widely used (Nimis and Taylor, Contrib Mineral Petrol 139:541–554, 2000) enstatite-in-clinopyroxene geothermometer, and confirms an improvement in performance of the new calibration relative to existing versions of the Ni-in-garnet geothermometer.

An Empirical Model for the Churning Losses Prediction of Fluid Flow Analysis in Axial Piston Pumps.

The manufacturing development of axial piston pumps usually takes the trend of high speed and miniaturization, and increases power density. Axial piston pumps are usually characterized as high speed to improve the power density; thus, high-speed churning losses caused by the internal rotating components stirring the oil can increase significantly. In order to improve the efficiency, more attention should be given to the churning losses in axial piston pumps, especially in high-speed conditions. Using the method of least-squares curve fitting, this paper establishes a series of formulas based on the churning losses test rig over a wide range of speeds, which enable accurate predictions of churning losses on the cylinder block and pistons. The reduction coefficient of flow resistance of multi-pistons as calculated. The new churning losses formula devoted to the cylinder block and rotating pistons was validated by comparison with experimental evidence in different geometries of axial piston pumps. According to the prediction model of churning losses, some valuable guidance methods are proposed to reduce the energy losses of the axial piston pump, which are the theoretical support for the miniaturization of axial piston pump manufacturing.

Evaluation of effective area of air piston gauge with limitations in piston–cylinder dimension measurements

The air piston gauge (APG) has been established at the National Physical Laboratory, India (NPLI) for Pascal realization since 2002. The APG at NPLI has been considered a transfer pressure standard because it has been calibrated against the primary pressure standard, i.e. ultrasonic interferometer manometer. As per existing international protocol, the APG establishment as a primary standard, the effective area (A e) of piston–cylinder (p–c) assembly and masses must be directly traceable to SI units. We have calculated A e and associated uncertainty of p–c assembly using the theory of rarefaction gas dynamics, which is based on dimension measurements. The value of A e is obtained for varying temperatures and radii of piston and cylinder in their respective uncertainty limits. The variation of the cylinder's inner radius within its uncertainty limit of 0.7 µm includes the expected effective area, i.e. 3.356 775 (5) cm2. The effective area’s expected values are obtained for the cylinder’s radius of 10.338 00 (2) mm, which is approximately 0.65 µm away from the value obtained from dimensional measurements and well within the uncertainty limit. Therefore, to get the effective area of 3.356 775 (5) cm2, the uncertainty of the cylinder’s radius should be at least one order less (similar to piston’s radius) than that of the present value. The precision in dimension measurement of the cylinder's internal radius is the critical parameter for effective area calculation of p–c assembly.

Electrical Conductivity of CO2 and H2O‐Bearing Nephelinitic Melt

AbstractDespite previous measurements on electrical conductivity of carbonate or carbonatite melts, the effect of several wt% CO2 on electrical conductivity of silicate melts has never been experimentally examined. This study investigated the CO2 effect on electrical conductivity of nephelinitic melt at 500°C–1,150°C and 0.5–1.0 GPa with 0.1–6.0 wt% CO2 and 0.2–1.6 wt% H2O in piston cylinder apparatus using sweeping frequency impedance analyses. Experimental results show that volatile‐bearing nephelinitic melt is highly conductive. In contrast with the strong enhancing effect of H2O on electrical conductivity of silicate melts, CO2 shows weak and even slightly negative influence on electrical conductivity of nephelinitic melt within the investigated CO2 range. Literature data of electrical conductivity of hydrous carbonated basaltic melts suggested strong positive CO2 effect at CO2 >10 wt%, but their model prediction at <6 wt% CO2 is consistent with our results. A weak CO2 effect implies that does not contribute to electrical conduction in any significant way at CO2 <6 wt%. Our results suggest that magnetotelluric survey is much less sensitive to CO2 content than to H2O content of crustal magma reservoirs.

Experimental settling, floatation and compaction of plagioclase in basaltic melt and a revision of melt density

Centrifuge-assisted piston cylinder experiments were conducted on plagioclase in basaltic melt at 1140–1250 °C, 0.42–0.84 GPa and mostly 1000 g. One set of experiments assesses the settling velocity of a dilute plagioclase suspension; a second sinks or floats plagioclase in a MORB-type melt exploring conditions of neutral buoyancy; and a third set examines floatation of plagioclase from an evolved lunar magma ocean composition. A compaction rate for plagioclase cumulates is established. The experiments demonstrate that neutral density of plagioclase An74 in a MOR-type tholeiitic basalt occurs at 0.59 ± 0.04 GPa (1200 °C), contrasting predictions by present models on melt density which yield a density inversion pressure at 0.10–0.15 GPa. In nature, the level of neutral buoyancy depends on melt composition; nevertheless, for the onset of plagioclase crystallization in dry tholeiitic basalts, our result is robust. As the molar volume of plagioclase is well known, the experimentally determined pressure of neutral buoyancy indicates a correction of -1.6% to previous density models for silicate melts. It follows that for (tholeiitic) layered mafic intrusions, plagioclase is negatively buoyant for early, relatively primitive, parent melts. In contrast, the extreme Fe enrichment of a fractionating lunar magma ocean leads to melt densities that let anorthite always float. Compaction φ/φ0 of experimental plagioclase cumulates is quantified to φ/φ0 = − 0.0582 log (Δρ·h·a·t) + 1.284, where φ0 is the porosity after settling (67 ± 2%), h the cumulate pile height, a acceleration and φ porosity as a function of time t. Gravitational-driven compaction in tens of m-thick plagioclase cumulate in basaltic magmas reaches down to ~ 40% porosity within hundreds of years, a timescales competing with characteristic cooling times of cumulate layers of mafic intrusions. To achieve plagioclase modes > 80% due to compaction, an additional overload of ~ 100 m (layers) of mafic minerals would be required. Compaction of a lunar anorthosite crust of 35 km to 20% porosity (i.e. ~ 90% plagioclase after crystallization of the interstitial melt) would require 30 kyrs.

Analysis of Weight loss in Reciprocating Wear Test of Cylinder Liner and Piston Ring Coated with Molybdenum

In this study, piston rings (PR) were coated with Molybdenum (Mo) powder High Velocity Oxygen Fuel (HVOF) coating method. In addition, the wear behavior of the Mo coated PR and the cast iron (CI) cylinder liner (CL) were examined. The parameters of load, temperature and revolution wear were optimized according to L27 array of Taguchi method in order to obtain minimum wear loss in wear tests. It has been determined from the experimental results that the most effective parameter for the minimum wear loss of both the PR and the CL was the load. Mathematical models were obtained using regression analysis. The results of the verification test of the optimization method and the experimental results were very close to each other. Wear maps have been created for the PR and CL. The analysis of the wear surfaces showed that the abrasive wear mechanism was dominant.

Implementation of hydraulically driven barrel shooting control by utilizing artificial neural networks

The success of the shooting of a moving vehicle can be achieved by providing barrel stabilization. In the meantime, it is necessary barrel angle must be positioned is instantaneously calculated accurately. In this paper, the required barrel elevation angle was calculated via artificial neural networks and the shooting success to a fixed target from a moving tank was investigated. For this purpose, a mathematical model of a tank, which has four degrees of freedom, with a barrel mounted on it has been utilized. The barrel is moved using an inverted slider mechanism. The system is driven hydraulically by considering the movement of the piston–cylinder pair in the inverted slider mechanism. The conventional PID control method has been preferred for angular position control of the barrel. Simulations have been performed with the MATLAB package program. System responses have been obtained graphically and the results have been presented in tabular form. It is seen that the pressure, flow, etc. obtained from the results overlap with the physical system. It is observed that the elevation angle of 10 degrees is captured and shot very well when the vehicle is stationary. In the moving state of the vehicle, the 10-degree elevation angle capture as well. In the moving case, there are tiny deviations in the target hit but these values can be considered to be reasonable levels. The deviation amount for the target 4 kilometers away is 16.28 meters.

Nitrogen solubility in basaltic silicate melt - Implications for degassing processes

The distribution of nitrogen between the different terrestrial reservoirs (core-mantle-atmosphere) and how this may have changed since the earliest planetary stages is uncertain. In particular, the primordial degassing processes of the magma ocean and its role in the formation of the atmosphere remains to be quantified. Since no geological samples can capture this early degassing process, we need to go through the thermodynamic modeling of the nitrogen solubility in silicate melt. We hence performed experiments on basaltic samples at fluid saturation in the C-H-O-N system, using an Internally Heated Pressure Vessel (IHPV) and Piston Cylinder (PC) in the pressure range 0.8 kbar to 10 kbar, temperature between 1200 and 1300 °C, and a wide range of fO2 conditions from IW + 4.9 to IW-4.7 (IW standing for the Iron-Wustite redox buffer). The nitrogen concentration in the quenched silicate melts at fluid saturation was analysed by secondary ion mass spectrometry (SIMS), and the speciation of the dissolved C-O-H species was determined by Fourier transform infrared spectroscopy (FTIR). We identified two nitrogen species in the silicate melt: N2 dominating at fO2 > IW and N3− at lower fO2. Using these data and a database constraining nitrogen concentration at fluid saturation from 1 bar to 10 kbar pressure, we calibrated a solubility law for nitrogen in basalts defining its P-T-fO2 dependences. This model expands the model of Libourel et al. (2003) to high pressure and higher C-O-H activities. It can be used to investigate the nitrogen degassing processes for different pressure, temperature and fO2 conditions relevant to planetary accretion and modern volcanism.

Y3Ba5Cu8Ox Superconductor Under Hydrostatic Pressure

Superconducting Y3Ba5Cu8O18 samples were prepared by standard solid-state reaction method in comparison with Y1Ba2Cu3O7 sample. Resistance vs. temperature of both samples was measured under hydrostatic pressures up to 0.93 GPa using a piston–cylinder pressure cell. Applying the pressure resulted in a decrease in resistance in the normal state and an increase of the transition temperature Tc for both polycrystalline samples. This phenomenon is then explained in terms of the increase in carrier concentrations. Our results show a positive value of $${\mathrm{dT}}_{\mathrm{c}}/\mathrm{dP}$$ =1.1 K/GPa and 1.4 K/GPa for Y123 and Y358, respectively.

Technology Upgrades and Reliability Analysis of a Tribometer for Performance Evaluation of Cylinder Piston Rings

The design of existing tribometers mainly focuses on normal contact and lubricant conditions and aims to evaluate the effect of the load, speed, and environmental conditions on the rubbing pair properties. The effect of the contact angle and variable speed on the rubbing pair properties is often not considered. In this study, a multidirectional adjustment tribometer is developed to evaluate the tribological behavior of cylinder liner–piston rings under dry sliding or oil lubrication conditions. The dynamic, specimen clamping, measuring, and control systems are redesigned according to the structural characteristics of the SKODA-SAVIN tribometer and special requirements of research on the net texture effect on tribological properties. Using LabVIEW software, a man–machine interface is designed to achieve converter control, data acquisition, and other functions. A fail-safe analysis is performed through reproducibility, comparability, and sensitivity tests. From the experiments, it is proved that the tester can provide more detailed, abundant, and reliable data for the performance testing and development of cylinder liner–piston ring materials.

Simulation Investigation of a Soft Hydraulic Artificial Muscle

This paper presents a soft hydraulic artificial muscle (SHAM) design, which replaces the cylinder, rod and piston in traditional hydraulic cylinder with soft structures. The presented muscle has the advantages of high output force level and good adaptability to environment. Modelling and simulation are conducted after introducing the working principle of the SHAM. Simulation results show that the output force can be as large as 160N with 0.8MPa input pressure. The effect of mixed air into the working fluid has also been investigated and discussed. Above advantages make the SHAM perfect for applications such as exoskeletons.

Evaluation of the trailbuilder hydraulic drive thermal preparation

One of the main problems in operation of road-building machines in conditions of low negative ambient temperatures is the hydraulic drive thermal preparation. The hydraulic equipment is located throughout the machine and need a local thermal warming otherwise its cold start results in its intense wear. We propose the warming method that comprises circulation of a prewarmed hydraulic fluid from the hydraulic tank through the piston and rod chambers of hydraulic cylinder without rod motion. This is ensured by installation of a bypass pipe and a valve connecting the hydraulic cylinder piston and rod chambers. To evaluate operability of the hydraulic cylinder warming system we determined the fluid circulation conditions depending on the fluid flow rate and its temperature. To check these conditions, we made calculations for a trailbuilder hydraulic drive with a ripper.

Earth’s volatile accretion as told by Cd, Bi, Sb and Tl core–mantle distribution

The timing and origin of volatile elements accretion on Earth has been and continues to be key questions, despite intense research scrutiny. Two end-member scenarios are usually proposed in which (1) volatile elements were delivered during the main phases of Earth’s accretion and underwent subsequent core–mantle differentiation, or (2) Earth accreted from largely dry and volatile-depleted material, with late addition of volatile-rich material after differentiation. Studying the behaviour of elements that are both volatile and siderophile in a metal–silicate equilibrium can help discriminate between those two scenarios by deconvolving the effect of siderophile processes such as the Earth’s differentiation from the effect of volatile processes. We report high-pressure and high-temperature metal–silicate equilibrium experiments that are used to trace the behaviour of four moderately siderophile and volatile elements: Cd, Bi, Sb and Tl. Experiments were performed in piston cylinder and multianvil presses between 2 and 20 GPa, from 1700 to 2600 K, in order to study the partitioning behaviour of these elements, including the relative influence of pressure, temperature, oxygen fugacity (fO2), and composition. Our results indicate that Cd, Bi, Sb and Tl partitioning coefficients are largely controlled by changes in temperature, pressure, fO2 and the S content of the metal phase. The pressure effect on Tl and Bi partitioning is measured for the first time and improves significantly the knowledge of Bi and Tl behaviour during core formation. Core formation modelling was used to reconcile the experimental data with observed abundances for different accretion scenarios. Homogeneous accretion with full core–mantle equilibration induces a massive segregation of Bi, Sb and Tl in the core, preventing reproduction of observed present-day mantle abundances. We find that a scenario in which the volatile elements are accreted in the last 10–20 % of the Earth’s accretion is the most suitable accretion process that is able to explain the abundances of Cd, Bi, Sb and Tl in Earth’s mantle. Partial core–mantle equilibration is necessary to reproduce Bi and Tl abundances. Our partitioning data also suggests that a 0.5 % chondritic late veneer may account for the Bi abundance measured in the bulk silicate Earth. These observations corroborate a growing wealth of evidence in support of this schematic heterogeneous accretion pathway.

Tribological performance of high-strength cast iron in lubricated contact containing carbon black

It is well-known that diesel engines generate soot during the combustion process, leading to a higher level of pollutant emissions and severe wear of contact surfaces in relative motion, resulting in worse engine performance. Carbon black has been used in laboratory wear tests to simulate soot in engine components such as piston rings and cylinder liners. However, there are still many questions to be answered, especially concerning the interaction between the particles, lubricants, and surface topography in contact. In the past years, compacted graphite iron (CGI) has been substituting grey cast irons in engine blocks because of its improved mechanical properties, resulting in thinner walls for lighter blocks and improving engines' performance. However, CGI's tribological behavior of higher strength grades has been scarcely studied due to its production cost and complexity. In the present study, two CGIs of high strength (JV450 and JV500 – ISO 16112/2017) were used as cylinder liners on ring-on-cylinder lubricated wear tests a CETR-UMT-Bruker tribometer. The cylinders' surfaces were honed to a plateau finishing, and the counterbody used was a commercial compression ring of nitrided stainless steel. Carbon black particles were added to commercial SAE CF-30 lubricant, simulating the presence of soot. The testing load and oil temperature were 175 N and 100 °C, respectively, creating a severe wear condition. Roughness measurements using interferometry were performed on the worn surfaces to compare with the plateau's topography and roughness parameters honing texture. The variation of structure height was used as the indicative of liner wear. Results showed almost the same coefficient of friction (COF) for all tested conditions. Still, the reason for each case was different, the ejection of graphite during sliding being more critical for JV450 iron. The carbon black was able to change the contact conditions. The high-strength GJV500 iron performed better, considering a tribological merit index (TMI), less sensitive to the presence of carbon black in the lubricant oil.

ススによって発生するシリンダボア・ピストンリング摩耗の解析(2) ―ディーゼルエンジンのEGR摩耗に対する表面分析からの解析―

ススによって発生するシリンダボア・ピストンリング摩耗の解析(2) ―ディーゼルエンジンのEGR摩耗に対する表面分析からの解析―

Ignition delay times of methane/diethyl ether (DEE) blends measured in a rapid compression machine (RCM)

Diethyl ether (DEE) is an interesting species for combustion for at least two reasons: On the one hand, it is used as a kind of ”worst case” reference substance for studies concerned with the prevention of accidental ignition events. On the other hand, it is also a candidate bio-fuel. For this reason, in this work, auto-ignition of two different ▪ /DEE-mixtures (90/10 and 95/5 mol-% ▪ /DEE) are studied in a rapid compression machine (RCM). In the RCM, the gas mixture is compressed in a piston–cylinder device up to 20bar and held under isochoric conditions at top dead center. Auto-ignition occurs after an ignition delay time (IDT). IDTs are measured for compression temperatures ranging between 515 and 925K, for both, stoichiometric and fuel-rich mixtures (equivalence ratio ϕ=2). The experimental data are compared to results of simulations involving detailed chemistry, as well as to other fuels investigated in the same RCM (results from literature).

Development and Research of Crosshead-Free Piston Hybrid Power Machine

This article considers the development and research of a new design of crosshead-free piston hybrid power machine. After verification of a system of simplifying assumptions based on the fundamental laws of energy, mass, and motion conservation, as well as using the equation of state, mathematical models of the work processes of the compressor section, pump section, and liquid flow in a groove seal have been developed. In accordance with the patent for the invention, a prototype of a crosshead-free piston hybrid power machine (PHPM) was developed; it was equipped with the necessary measuring equipment and a stand for studying the prototype. Using the developed mathematical model, the physical picture of the ongoing work processes in the compressor and pump sections is considered, taking into account their interaction through a groove seal. Using the developed plan, a set of experimental studies was carried out with the main operational parameters of the crosshead-free PHPM: operating processes, temperature of the cylinder–piston group and integral parameters (supply coefficient of the compressor section, volumetric efficiency of the pump section, etc.). As a result of numerical and experimental studies, it was determined that this PHPM design has better cooling of the compressor section (decrease in temperature of the valve plate is from 10 to 15 K; decrease in temperature of intake air is from 6 to 8 K, as well as there is increase in compressor and pump section efficiency up to 5%).