This research focuses on improving the efficiency of four-stroke diesel engines, widely used in land transport. The study looks at how using nanofluids and different coolant combinations can impact ...thermophysical properties, such as convective heat transfer coefficient, Nusselt number, and entropy values. The Mercedes-Benz OM502 v8 2023 engine is used in the study. The goal is to improve radiator cooling processes and achieve economic savings. Causing more improvements in nanofluids thermophysical specifications according to available literature has led us to consider titania (TiO2), silica (SiO2), and alumina (Al2O3) nanoparticles. Nanofluids with the mentioned compositions, besides nanoparticles with 0.2%–0.8% vol. concentrations, have been studied, and eventually, the most efficient nanofluid composition has been selected as the optimal coolant. The validity of the utilized numerical technique is verified by comparing the method output with the Mercedes-Benz OM502 V8 2023 engine catalog. Results of our numerical studies show a 75.1% and 128.1% improvement in heat transfer rate along with a coolant temperature drop at the outlet by 23.8 °C and 21.4 °C at coolant's inlet temperatures of 85 °C and 95 °C. Furthermore, economic analyses have demonstrated that the use of optimal coolant composition can yield annual cost savings of approximately $2700.
Recent developments have rendered the Dual Fuel (DF) engines an attractive alternative solution for achieving cost-efficient compliance to environmental regulations. The present study focuses on the ...safety investigation of a marine DF engine in order to identify potential safety implications. This investigation is based on an integrated engine model, which was developed in GT-ISE™ software and is capable of predicting both the engine steady-state behaviour and transient response. The model includes the engine thermodynamic simulation module as well as the engine control system functional module; the latter is responsible for implementing the ordered load changes and the operating mode switching. The developed model is first validated against available published data and subsequently used to simulate several test cases with fuel changes, from gas to diesel and diesel to gas with rapid and with delayed wastegate valve operation. The derived simulation results are used to investigate the potential safety implications that can arise during the engine operation. The results demonstrate that the engine-turbocharger matching as well as the wastegate control are critical parameters for ensuring the compressor surge free operation during gas to diesel modes transition.
Abbreviations: 0D: zero-dimensional; 1D: one-dimensional; BMEP: brake mean effective pressure; CO
2
: carbon dioxide; DF: dual fuel; D/G: diesel generator; DTG: diesel to gas fuel modes switching; ECA: emission control area; ECS: engine control system; EEDI: energy efficiency design index; GTD: gas to diesel modes switching; HFO: heavy fuel oil; IMO: International Maritime Organization; LFO: light fuel oil; LNG: liquefied natural gas; MCR: maximum continuous rating; NOx: nitrogen oxides; PHA: preliminary hazard analysis; PI: proportional-integral; SOx: sulphur oxides; TC: turbocharger; WG: wastegate; λ: air-fuel equivalence ratio
Problem. Single-cylinder four-stroke engines are used as a power plant for vehicles participating in international economical competitions Shell «Eco-maratthon». Many of the teams in the ...qualification «Forced-ignition internal combustion engines» use HONDA GX 25 and GX 35 engines. Therefore, it is important to know the mechanical losses of such engines to find ways to reduce them. The aim of the study is to determine the mechanical losses by scrol-ling the crankshaft with an electric motor DC-ED-25. For experimental determination of mechanical losses of the GX 25 engine, a special stand was created on the bed of which the tested motor and electric motor are mounted. The paper proposes a methodology for conducting an experimental study and the results obtained by two methods of mounting an electric motor on a bed. In the first case, the electric motor was fixed rigidly on the bed. In this case, the electric power was determined and, knowing the efficiency of the electric motor, the power of mechanical losses was determined. In the second case, the motor housing was installed in rolling bearings with the condition of free rotation around the axis. During the tests, the mechanical moment acting on the body was determined using a strain gauge. Good experimental data were obtained in different ways. After statistical processing of the research results, empirical dependences for power and average pressure of mechanical losses are proposed. The method of scrolling the engine crankshaft by an external source is characterized by the simplicity of organization and measurement during the experiment. However, a more reliable method for determining mechanical losses is the method of comparing the indicator and effective power.
In this study, a model is developed to simulate the dynamics of an internal combustion engine, and it is calibrated and validated against reliable experimental data, making it a tool that can ...effectively be adopted to conduct emission predictions. In this work, the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine, a four-stroke engine used in the maritime field. Results from the bench tests are used for the calibration of the model. Finally, the calibration of the model and its validation with full-scale data measured at sea are presented. The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions, which are compared with similar results obtained with emission factors. The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7% on power, torque, and consumption. The model provides encouraging results, suggesting further applications, such as in the study on transient conditions, coupling of the engine model with the ship model for a complete simulation of the operating conditions, and optimization studies on consumption and emissions. The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work.
The current work experimentally and theoretically studied the effect of water
injection on improving the performance of three different types of
single-cylinder internal combustion engines. The first ...engine is a four-stroke
diesel, the second is a four-stroke gasoline, and the third is a two-stroke
gasoline engine. Different amounts of water were injected relative to fuel
consumption for the three engines to find how it affected the performance,
exhaust gas temperatures, and emissions. Comparing the experimental and
theoretical results was done to determine the effect of spraying water on
lowering the temperatures of the exhaust gases, increasing the thermal
efficiency, and lowering specific fuel consumption. The experimental results for
the various tested engines show that, in general, the exhaust gas temperature
and gas emission decreases by increasing the mass of water injection; these
differences vary based on the engine and the operating conditions. Water
injected at the inlet of the gasoline engine reduces the overall emissions
greater than with the diesel engine and the two-stroke engine. The current
laboratory experiments have shown and confirmed by theoretical analyses that
spraying water at the inlet of engines reduces braking fuel consumption by a
maximum of 10% with an increase in thermal efficiency by up to a maximum of 4.5%
and reducing emissions of nitrogen oxides (NOx) and exhaust gas temperature by
up to 35%.
We present the results of a numerical model which has been developed for estimating the contribution to the methane slip from different sources in a four-stroke dual-fuel marine engine running on ...natural gas. The model is a thermodynamic three-zone zero-dimensional full engine cycle model and considers methane slip contributions from short-circuiting, crevices and wall quenching. The model is applied to analyze the methane slip from a four-stroke dual-fuel medium speed marine engine using natural gas as primary fuel. At low loads, wall quenching is found to be the dominant contribution to the methane slip. At full load, the wall quenching contribution is comparable to the level of the short-circuiting and crevice contributions which only vary relatively little with load. At 75% load, the contribution from short-circuiting is highest. In addition, we found that in-cylinder post-oxidation of unburned fuel remaining after the main combustion is negligible.
The use of palm oil as a base stock for an environmentally friendly lubricant for small four-stroke motorcycle engines is investigated. Palm oil was blended with mineral oil at different compositions ...to the viscosity requirement of commercial lubricant. A liquid additive package was added to improve the viscosity of the lubricant. A blend that meets the viscosity requirement was then chosen for physical and chemical property characterization and subjected to an engine test. The blend consists of 50.6% (wt.) palm oil, 41.6% mineral oil, and 7.8% additive package. The properties evaluated include viscosity, viscosity index, flash point, foaming characteristics, and wear scar. The engine performance and emission tests were carried out with a 125-cc motorcycle on a chassis dynamometer using a Bangkok Driving Cycle. Compared to a mineral-based commercial oil, the palm oil-based lubricant exhibits superior tribological properties, but offers no clear advantage on engine and emission performance.
The gasoline fueled single cylinder generator engines are well established and available in the market with reasonable price, in the other hand the biogas fueled engine for electric generator is not ...well established yet. The purpose of this research is to find simple conversion method from gasoline to biogas fueled of the single cylinder four stroke engines. For this purpose, the biogas should be upgraded to the level of zero H2S impurity and zero level of H2O content. The carburetor of the gasoline engine was replaced and only component of the mixer of the fuel and air were used. The intake of the biogas fueled should be completed with valve that can be opened automatically by vacuum of the suction stroke of the engine. To increase the performance of the engine, the liquefied petroleum gas (LPG) was added to the mixture up to 80% of biogas and 20% LPG.
The new emission legislation for sea-going vessels issued by the International Maritime Organization (IMO) requires drastic reduction in exhaust gas nitrogen oxides (NOx), and the combination of ...different primary methods can be an interesting solution without increasing remarkably the machinery. In this paper, the Miller cycle and the dilution with exhaust gas in the combustion chamber were tested to reach the Tier III limits for a four-stroke marine engine. In particular, the Miller cycle is used to reduce the in-cylinder temperature, and lower oxygen content in the combustion chamber is realized with cooled exhaust gas recirculation (EGR). Despite a remarkable reduction in NOx, the main drawback was a significant increase in fuel consumption. Split injection is combined with the abovementioned methods, in order to improve the engine efficiency. The novelty of this study consists in the simultaneous use of a split fuel injection, the Miller cycle and EGR in a marine-size application. Along this study, combining Miller timing with a relatively low EGR rate reduces NOx emissions by 90%. On the other hand, split injection does not bring significant advantages in fuel economy, although the results with very early pilot injection suggest further studies to be realized.
The Fourier Engine Collins, Michael D.
IEEE access,
2018, Volume:
6
Journal Article
Peer reviewed
Open access
Each combustion chamber of the Fourier engine is open to multiple cylinders, which have pistons connected to crankshafts that rotate at different rates. The displacements of the individual cylinders ...and the relative phases of the pistons are selected according to a Fourier approximation of a prescribed time dependence of the volume of the combustion chamber. The parameters are selected so that the duration of the intake and ignition strokes is greater than the duration of the compression and exhaust strokes. As the speed of an engine increases, the power curve initially climbs approximately linearly, but it levels off as intake and ignition become less efficient at high rpm. By increasing the duration of these strokes relative to the duration of the other strokes, it may be possible to allow the power curve to climb higher before leveling off.
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