Improving the energy efficiency of a 6ChN13/15 gas engine with a Miller cycle by optimizing the valve timing

Trudy NAMI ◽  
2022 ◽  
pp. 41-52
Author(s):  
A. V. Kozlov ◽  
V. A. Fedorov ◽  
K. V. Milov
Keyword(s):  
Numerical Modeling ◽  
Thermodynamic Cycle ◽  
Practical Significance ◽  
Miller Cycle ◽  
Gas Distribution ◽  
Gas Engine ◽  
Model Studies ◽  
Air Supply ◽  
Scale Experiment ◽  
Supply Systems

Introduction (problem statement and relevance). The object of research in this work is an inline six-cylinder gas engine 6ChN13/15 with a Miller thermodynamic cycle. On the basis of its computer model studies minimization of the specific effective fuel consumption has been reached due to variation study of gas distribution and air supply systems parameters.The purpose of the study was to investigate the parameters regulation effect of gas distribution and air supply systems on the performance of a 6ChN13/15 gas engine with a Miller cycle on the external speed characteristic basing on numerical modeling.Methodology and research methods. The research was carried out by the method of computer simulation. Numerical modeling was made on the basis of data obtained during a full-scale experiment of a 6ChN13/15 gas engine with Miller thermodynamic cycle.Scientific novelty and results. A comparative analysis of a gas engine optimization results has been carried out. The results obtained will be used to create a gas engine and its further optimization by controlling the working process and the air supply system.Practical significance. The results obtained may be of interest to truck car manufacturers and engine specialists.

scholarly journals Computational studies of the influence of variable valve timing on the performance of a gas engine with Miller’s thermodynamic cycle

2021 ◽  
Vol 2061 (1) ◽  
pp. 012066
Author(s):  
K V Milov
Keyword(s):  
Internal Combustion Engines ◽  
Computer Modelling ◽  
Thermodynamic Cycle ◽  
Valve Lift ◽  
Variable Valve Timing ◽  
Miller Cycle ◽  
Valve Timing ◽  
Gas Engine ◽  
Lift Height ◽  
Variable Valve

Abstract Current development trends in the field of internal combustion engines aim at regulating all processes of the engine and individual units. A converted diesel to gas engine with Miller thermodynamic cycle is more energy efficient at partial loads than a gas engine with Otto thermodynamic cycle. The Miller cycle engine with variable valve timing and valve lift has been investigated to improve performance and energy efficiency across the load range. The aim of the work is to study the influence of the displacement of the valve timing phases of the intake and exhaust camshafts and the valve lift height on the performance of the gas engine with the Miller cycle. Computer modelling was based on data obtained from the full-scale experiment on the gas engine with the Miller thermodynamic cycle.

scholarly journals A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1051
Author(s):  
Jungmo Oh ◽  
Kichol Noh ◽  
Changhee Lee
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Expansion Ratio ◽  
Boost Pressure ◽  
Miller Cycle ◽  
Compression Pressure ◽  
Air Mass ◽  
Atkinson Cycle

The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.

Doppler echo evaluation of pulmonary venous-left atrial pressure gradients: human and numerical model studies

2000 ◽  
Vol 279 (2) ◽  
pp. H594-H600 ◽  
Author(s):  
Michael S. Firstenberg ◽  
Neil L. Greenberg ◽  
Nicholas G. Smedira ◽  
David L. Prior ◽  
Gregory M. Scalia ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Left Atrial ◽  
Atrial Pressure ◽  
Left Atrial Pressure ◽  
High Fidelity ◽  
Pressure Gradients ◽  
Bernoulli Equation ◽  
Venous Flow ◽  
Model Studies ◽  
Pulmonary Venous Flow

The simplified Bernoulli equation relates fluid convective energy derived from flow velocities to a pressure gradient and is commonly used in clinical echocardiography to determine pressure differences across stenotic orifices. Its application to pulmonary venous flow has not been described in humans. Twelve patients undergoing cardiac surgery had simultaneous high-fidelity pulmonary venous and left atrial pressure measurements and pulmonary venous pulsed Doppler echocardiography performed. Convective gradients for the systolic (S), diastolic (D), and atrial reversal (AR) phases of pulmonary venous flow were determined using the simplified Bernoulli equation and correlated with measured actual pressure differences. A linear relationship was observed between the convective ( y) and actual ( x) pressure differences for the S ( y = 0.23 x + 0.0074, r = 0.82) and D ( y = 0.22 x + 0.092, r = 0.81) waves, but not for the AR wave ( y = 0.030 x + 0.13, r = 0.10). Numerical modeling resulted in similar slopes for the S ( y = 0.200 x − 0.127, r = 0.97), D ( y = 0.247 x − 0.354, r= 0.99), and AR ( y = 0.087 x − 0.083, r = 0.96) waves. Consistent with numerical modeling, the convective term strongly correlates with but significantly underestimates actual gradient because of large inertial forces.

Analysis of the influence of the angle of inclination of solar panels on the operation of the grid using renewable energy sources

2020 ◽  
Vol 23 (2) ◽  
pp. 70-76
Author(s):  
D. OSTRENKO ◽  
◽  
Oleksandr Kollarov ◽  
Keyword(s):  
Renewable Energy Sources ◽  
Dynamic Change ◽  
Solar Panel ◽  
Practical Significance ◽  
Electrical Network ◽  
Solar Panels ◽  
Solar Insolation ◽  
Optimal Method ◽  
Photovoltaic Panels ◽  
Model Studies

When considering the operation of the solar panel and performing modeling of its operation in [1], such input parameters as the level of solar insolation (the amount of light coming to the SP) and the value of the outside temperature on the solar panels themselves were taken into account. However, such an important parameter as the angle of inclination of the solar panels was not taken into account in such modeling. The value of this parameter takes into account, of course, the level of solar insolation, because the level of light that enters the JV directly depends on the angle at which they are located. However, it has not been considered that sensors (or luxmeters) for measuring illumination may be located at an angle other than the angle of inclination of the solar panel or, more importantly, the solar panels themselves due to their design features may not receive enough solar radiation. can take into account light sensors. This possibility exists at an angle of inclination close to zero, ie at dawn and sunset. This article is designed to take into account the influence of the angle of inclination of solar panels through the use of empirical dependencies and to test the theoretical foundations that have been formed in previous articles [1-4]. This article demonstrates the practical significance of taking into account the value of the angle of inclination of solar panels in the calculations of the photovoltaic plant. To do this, we first analyzed the state of the issue and the available methods of changing the angle of inclination in the operation of the electrical network with photovoltaic panels. Secondly, the influence of the geometric arrangement of the panels was taken into account when constructing the mathematical model. Studies have concluded that the optimal method of controlling the angle of inclination of photovoltaic panels is its seasonal change. After all, the application of this method increases the power output of RES with an average of 35% in summer and 10% in winter compared to fixed panels and does not require additional and sometimes very expensive equipment compared to the dynamic change of angle during the day. Further use of the proposed method will bring the values obtained during the simulation to the practical ones obtained when working with the installation.

AIR SUPPLY SYSTEMS

1969 ◽  
pp. 113-125
Author(s):  
J. FLACK ◽  
A.J.S. BENNETT ◽  
R. STRONG ◽  
LEONARD J. CULVER
Keyword(s):  
Air Supply ◽  
Supply Systems

scholarly journals Conversion of gas engine waste heat into cold using absorption chillers

2020 ◽  
Vol 168 ◽  
pp. 00046
Author(s):  
Georgii Karman ◽  
Yurii Oksen ◽  
Olena Trofymova ◽  
Yurii Komissarov ◽  
Borys Dizhevskyi ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Waste Heat ◽  
Lithium Bromide ◽  
Thermodynamic Cycle ◽  
Cooling Capacity ◽  
Coolant Temperature ◽  
Gas Engine ◽  
Absorption Chillers ◽  
Full Conversion ◽  
Heating Medium

A possibility of gas engine waste heat conversion into cold for air conditioning in mines using lithium bromide absorption chillers is investigated. Dependencies of parameters of a thermodynamic cycle and energy indicators of chillers on temperatures of a heating medium and a coolant are obtained using mathematical modelling. It is shown that it is rational to use two chillers with sequential movement of a heating medium and a coolant through them in opposite directions for a full conversion of gas engine waste heat. COP of such a system is 0.733. This allows obtaining 2140 kW of cooling capacity with a coolant temperature of 7 °C when using a gas engine JMS-620 by Jenbacher.

Turbine Stator Well CFD Studies: Effects of Coolant Supply Geometry on Cavity Sealing Performance

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Antonio Andreini ◽  
Riccardo Da Soghe ◽  
Bruno Facchini
Keyword(s):  
Air Cooling ◽  
Sector Model ◽  
Engine Efficiency ◽  
Air Supply ◽  
Sealing Performance ◽  
Computational Fluid Dynamics Cfd ◽  
Cooling Air ◽  
Supply Systems

The increase of aeroengine performance through the improvement of aerodynamic efficiency of core flow is becoming more and more difficult to achieve. However, there are still some devices that could be improved to enhance global engine efficiency. Particularly, investigations on the internal air cooling systems may lead to a reduction of cooling air with a direct benefit to the overall performance. At the same time, further investigations on heat transfer mechanisms within turbine cavities may help to optimize cooling air flows, saving engine life duration. This paper presents a computational fluid dynamics (CFD) study aimed at the characterization of the effects of different geometries for cooling air supply within turbine cavities on wall thermal effectiveness and sealing mass flow rate. Several sealing air supply geometries were considered in order to point out the role of cooling air injection position, swirl number, and jet penetration on the cavities’ sealing performance. Steady state calculations were performed using two different computational domains: the first consists of a sector model of the whole turbine including the second stator well, while the second is a cut-down model of the stator well. Thanks to the simplified geometry of the test rig with respect to actual engines, the study has pointed out clear design suggestions regarding the effects of geometry modification of cooling air supply systems.

scholarly journals Ideal Thermodynamic Cycle Analysis for the Meletis-Georgiou Vane Rotary Engine Concept

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Demos P. Georgiou ◽  
Nikolaos G. Theodoropoulos ◽  
Kypros F. Milidonis
Keyword(s):  
Thermodynamic Cycle ◽  
Miller Cycle ◽  
Gas Temperature ◽  
Expansion Chamber ◽  
Rotary Engine ◽  
Chamber Volume ◽  
Elevated Pressures ◽  
Gas Recirculation ◽  
Engine Concept ◽  
Reduced Pressures

The Meletis-Georgiou is a patented Vane Rotary Engine concept that incorporates separate compression-expansion chambers and a modified Otto (or Miller) cycle, characterized by (Exhaust) Gas Recirculation at elevated pressures. This is implemented by transferring part of the expansion chamber volume into the compression one through the coordinated action of two vane diaphragms. This results into a very high gas temperature at the end of the compression, something that permits autoignition under all conditions for a Homogeneous Compression Ignition (HCCI) version of the engine. The relevant parametric analysis of the ideal cycle shows that the new cycle gives ideal thermal efficiencies of the order of 60% to 70% under conditions corresponding to homogeneous compression engines but at reduced pressures when compared against the corresponding Miller cycle.

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