scholarly journals Comparative analysis of marine diesel engines by ultimate efficiency increase under direct air flow control

2021 ◽  
Vol 2021 (2) ◽  
pp. 43-54
Author(s):  
Vyacheslav Leontievich Konyukov
Keyword(s):  
Comparative Analysis ◽  
Diesel Engine ◽  
Pressure Drop ◽  
Diesel Engines ◽  
Air Flow ◽  
Maximum Pressure ◽  
Stable Operation ◽  
Marine Diesel ◽  
Effective Angle ◽  
Load Characteristics

The paper presents a comparative analysis of the operational parameters and parameters of marine diesel engines obtained as a result of computational and theoretical studies with direct control of air flow using an adjustable turbocharger nozzle to ensure the maximum allowable efficiency of diesel engines. The objects under study are: two-stroke marine diesel engine, operating on the screw characteristics; marine four-stroke diesel working on the screw characteristics; marine four-stroke diesel working on the load characteristics. As a result of the rotation of the blades of the adjustable nozzle in the direction of reducing the angle of their installation the diesel engine efficiency increases. However, the maximum pressure of the cycle also increases, the pressure drop decreases during purging the cylinders, the effective angle of gas exit from the turbine nozzle decreases, and the compressor's surge stability margin changes. There has been studied the design potential of diesel engines for the maximum increase in their efficiency, which made it possible to accept the stable operation of the compressor in all the studied modes. In the course of the research, boundary values were found for the maximum pressure of the diesel cycle, the pressure drop for purging the cylinders and the effective angle of flow exit from the nozzle apparatus, beyond which the specified parameters did not go beyond all the studied modes of operation of diesels. Taking into account the limitations of the greatest potential for improving efficiency in the equity modes of loads has a four-stroke diesel engine, operating on the screw characteristics, the smallest capacity is the same petrol, but working on the load characteristics.

Air Flow Analysis in Square Duct Bend

2014 ◽  
Vol 695 ◽  
pp. 622-626 ◽  
Author(s):  
Mohamad Nor Musa ◽  
Mohd Nurul Hafiz Mukhtar
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Cross Section ◽  
Air Flow ◽  
Flow Analysis ◽  
Maximum Velocity ◽  
Maximum Pressure ◽  
Air Velocity ◽  
Square Duct ◽  
Inlet Velocity

This paper present new result for experimental analysis of air flow velocity and pressure distributions between two ducts bend: (1) 90° duct bend with a single turning vane having 0.03m radius and (2) 90° duct bend with double turning vane, in 0.06 × 0.06 m duct cross section. The experiment used five different Reynolds numbers chosen between the ranges 1 ×104 and 6×104. Each experiment has four point measurements: (1) point 1 and point 2 at cross section A-A and (2) point 3 and point 4 at cross section B-B. The first experimental study used single turning vane radius 0.03m with inlet air velocity from 2.5m/s to 12.2m/s. And for the second experiment that used square turning vane with 0.03m radius. In experiment 2, the inlet air velocity also start from 2.5m/s to 12.2m/s. From analysis results, the pressure drop in experiment 1 is higher than experiment 2. As example the maximum pressure drop at 7.5m/s inlet air velocity between point 1 and 3 was found to be 71.6203 Pa in experiment 1 as compared to 61.8093 Pa in experiment 2. The velocity after duct bend is greater when using double turning vane compare used single turning vane as maximum velocity at point 3 in experiment 2 compare to velocity at point 3 in experiment 1 that is 55.677× 10-4 m/s and 54.221× 10-4 m/s. The velocity at duct wall is equal to zero. When increase the value of Reynolds number or inlet velocity, the maximum velocity and total pressure also increase. For example in experiment 1 at point 1, the velocity is 48.785 × 10-4 m/s at Reynolds number 1 ×104 and velocity 65.115×10-4 m/s at Reynolds number 12.2 ×104 . Velocity flow in duct section are lower than inlet velocity. In experiment 1, the inlet velocity is 2.5m/s meanwhile the maximum velocity in the duct section at point 2 is 73.075×10-4 m/s that is much more lower than inlet velocity.

Experimental Study of Diesel Engine Cycle-to-Cycle Variation—Part II: Correlation of Ignition Delay and Cylinder Pressure Variation

1989 ◽  
Vol 33 (04) ◽  
pp. 310-317
Author(s):  
M. Soonnadum ◽  
R. Latorre ◽  
D. Charnews
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Poor Correlation ◽  
Maximum Pressure ◽  
Cylinder Pressure ◽  
Cylinder Test ◽  
Cycle Variation ◽  
Marine Diesel ◽  
Engine Excitation ◽  
Variation Part

Marine diesel engine excitation can occur from the cycle-to-cycle variation in the engine output. The cycle-to-cycle variation in maximum cylinder pressure is often used to represent this variation. Recent tests indicate a poor correlation between the variation in maximum pressure and variation in pressure impulse (PI). This paper summarizes the results of systematic experiments to determine the cycle-to-cycle variation in maximum cylinder pressure, ignition delay (ID), and corresponding ignition pressure in a single-cylinder test diesel engine at various rpm and compression ratios. Comparisons show that there is a high correlation between the cycle-to-cycle variation in ID and PI. Consequently, the variation in the ignition delays should be used instead of the maximum pressure.

Design and Optimization of the Restrictor of a Race Car

2015 ◽  
Author(s):  
Prithvi Raj Kokkula ◽  
Shashank Bhojappa ◽  
Selin Arslan ◽  
Badih A. Jawad
Keyword(s):  
Fluid Dynamics ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Air Flow ◽  
Intake Manifold ◽  
Maximum Pressure ◽  
Cross Sectional ◽  
Formula Sae

Formula SAE is a student competition organized by SAE International. The team of students design, manufacture and race a car. Restrictions are imposed by the Formula SAE rules committee to restrict the air flow into the intake manifold by putting a single restrictor of 20 mm. This rule limits the maximum engine power by reducing the mass flow rate flowing to the engine. The pull is greater at higher rpms and the pressure created inside the cylinder is low. As the diameter of the flow path is reduced, the cross sectional area for flow reduces. For cars running at low rpm when the engine requires less air, the reduction in area is compensated by accelerated flow of air through the restrictor. Since this is for racing purpose cars here are designed to run at very high rpms where the flow at the throat section reach sonic velocities. Due to these restrictions the teams are challenged to come up with improved restrictor designs that allow maximum pressure drop across the restrictor’s inlet and outlet. The design considered for optimizing a flow restrictor is a venturi type having 20 mm restriction between the inlet and the outlet complying with the rules set by Formula SAE committee. The primary objective of this work is to optimize the flow restriction device that achieves maximum mass flow and minimum pull from the engine. This implies the pressure difference created due to the cylinder pressure and the atmospheric pressure at the inlet should be minimum. An optimum flow restrictor is designed by conducting analysis on various converging and diverging angles and coming up with an optimum value. Venturi type is a tubular pipe with varying diameter along its length, through which the fluid flows. Law of governing fluid dynamics states that the “Velocity of the fluid increases as it passes through the constriction to satisfy the principle of continuity”. An equation can be derived from the combination of Bernoulli’s equation and Continuity equation for the pressure drop due to venturi effect. [1]. A Computational Fluid Dynamics (CFD) tool is used to calculate the minimum pressure drop across the restrictor by running a series of analysis on various converging and diverging angles and calculating the pressure drop. As a result, an optimum air flow restrictor is achieved that maximizes the mass flow rate and minimizes the engine pull.

Computer aided study of the transient performances of a highly rated sequentially turbocharged marine diesel engine

1998 ◽  
Vol 212 (3) ◽  
pp. 185-196 ◽  
Author(s):  
X Tauzia ◽  
J F Hetet ◽  
P Chesse ◽  
G Crosshans ◽  
L Mouillard
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Marine Diesel Engine ◽  
Computer Aided ◽  
Compressor Surge ◽  
Marine Diesel ◽  
Valve Opening ◽  
Transient Phases ◽  
Good Agreement

The sequential turbocharging technique described in this paper leads to an improvement in the operations of highly rated diesel engines, in particular at part loads (better air admission). However, transient phases such as a switch from one turbocharger to two turbochargers can be difficult, mainly because of the inertia of the turbochargers. In order to simulate the dynamics of turbocharged diesel engines, the SELENDIA software has been extended. When applied to two different engines (12 and 16 cylinders), the program shows good agreement with the experimental data. Moreover, the compressor surge has been investigated during faulty switch processes. The software has then been used for predictive studies to evaluate the possibility of adapting sequential turbocharging to a 20-cylinder engine and to calibrate the optimum switching conditions (air and gas valve opening timing).

scholarly journals Computational and experimental determination of flame radiation parameters in the combustion chamber of a marine diesel engine

2020 ◽  
pp. 98-102
Author(s):  
Б.И. Руднев ◽  
О.В. Повалихина
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Combustion Chamber ◽  
Experimental Method ◽  
Diesel Engines ◽  
Flame Temperature ◽  
Marine Diesel Engine ◽  
Gas Temperature ◽  
Flame Radiation ◽  
Marine Diesel

Температура пламени и степень черноты определяют его собственное излучение. Однако оценка указанных параметров на стадии проектирования судовых дизелей представляет собой трудную и еще пока нерешенную проблему. Последнее обусловливается сложностью достоверного математического моделирования процесса сгорания топлива в дизельных двигателях и весьма высокой стоимостью экспериментальных исследований в этой области. Целью данной статьи является разработка расчетно-экспериментального метода определения параметров излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36. Показано, что оценка величины температуры пламени в камере сгорания в функции угла поворота коленчатого вала может быть выполнена по температуре газов, найденной из экспериментальной или расчетной индикаторной диаграммы и специального параметра. Последний определяется на основании зависимости, полученной путем обобщения экспериментальных данных по измерениям температуры пламени на ряде дизельных двигателей. Представлены результаты по температуре пламени для судового дизеля 6 ЧН 24/36, полученные с использованием разработанного расчетно-экспериментального метода. Установлено, что с ростом нагрузки температура пламени возрастает. При этом в диапазоне изменения нагрузки дизеля от 50% до 100% от номинальной мощности увеличение температуры пламени примерно в два раза превышает увеличение температуры газов. Использование полученных результатов для оценки собственных потоков излучения пламени в камере сгорания судового дизеля 6 ЧН 24/36 и сопоставление их с известными экспериментальными данными показало сходимость в пределах 10 – 15%. The flame temperature and radiating power are determined with its own radiation. However, the assessment of these parameters at the design stage of marine diesel engines is a complicated and still unsolved problem. The latter is due to the complexity of reliable mathematical modeling of the fuel combustion process in diesel engines and the very high cost of experimental research in this area. The purpose of this article is to develop a computational and experimental method for determining the parameters of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36. It is shown that the estimation of the value of flame temperature in the combustion chamber as a function of the crankshaft rotation angle can be performed using the gas temperature found from the experimental or calculated indicator diagram and a special parameter. The latter is determined on the basis of the dependence obtained by generalizing experimental data of the flame temperature measurements at a number of diesel engines. The results on the flame temperature for marine diesel engine 6 ChN 24/36, obtained using the developed computational and experimental method, are presented. It has been found that the flame temperature increases with increasing load. At the same time, in the range of diesel load variation from 50% to 100% of the nominal power, an increase in the flame temperature is approximately twice more than an increase in the gas temperature. The use of the results obtained to assess the intrinsic fluxes of flame radiation in the combustion chamber of marine diesel engine 6 ChN 24/36 and their comparison with the known experimental data showed the convergence within 10 - 15%.

scholarly journals Assessment of the impact of the technical condition of the cylinder-piston group parts on nitrogen oxide emissions

2021 ◽  
Vol 2131 (5) ◽  
pp. 052058
Author(s):  
O Roslyakova ◽  
V Zaitsev ◽  
D Panov
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Technical Condition ◽  
Working Process ◽  
Mixture Formation ◽  
Special Equipment ◽  
Harmful Emissions ◽  
Marine Diesel ◽  
Cylinder Piston ◽  
The Impact

Abstract Nowadays, a lot is paid to environmental protection issues, including those related to reducing emissions from ships of the sea and river fleet, which is reflected in many works. Constant control over the content of harmful emissions in the environment forces us to deal with the issues of reducing emissions from diesel engines at the design stages and during operation. The solution to this problem allows us to consider 2 directions: constructional and the use of special equipment for capture and neutralization. In the best case, a combined method can be used, i.e. constructional with the use of capturing equipment for harmful components in diesel exhaust gases. This paper presents an analysis of the influence of various factors that reduce the load on the atmospheric air from nitrogen oxides of marine diesel engines, namely, from the operating settings of the diesel engine and its wear. On the ships of the river fleet, diesel engines are used with various mixture formation with volumetric, volumetric-film, vortex mixture formation. The leader in the listed group is the volumetric mixture engines. The paper provides an assessment of the research carried out to analyze various methods of influencing the working process of a diesel engine - the type of mixture formation, wear of the cylinder sleeve in order to determine their influence on the formation of NOx emissions.

An Experimental Study on Fuel Economy Improvement of a Marine Diesel Engine Using a Sequential Turbocharging System

2018 ◽  
Author(s):  
Hechun Wang ◽  
Xiannan Li ◽  
Yinyan Wang ◽  
Hailin Li
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Diesel Engines ◽  
Engine Speed ◽  
Single Stage ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Engine Operation ◽  
Marine Diesel ◽  
High Torque

Marine diesel engines usually operate on a highly boosted intake pressure. The reciprocating feature of diesel engines and the continuous flow operation characteristics of the turbocharger (TC) make the matching between the turbocharger and diesel engine very challenging. Sequential turbocharging (STC) technology is recognized as an effective approach in improving the fuel economy and exhaust emissions especially at low speed and high torque when a single stage turbocharger is not able to boost the intake air to the pressure needed. The application of STC technology also extends engine operation toward a wider range than that using a single-stage turbocharger. This research experimentally investigated the potential of a STC system in improving the performance of a TBD234V12 model marine diesel engine originally designed to operate on a single-stage turbocharger. The STC system examined consisted of a small (S) turbocharger and a large (L) turbocharger which were installed in parallel. Such a system can operate on three boosting modes noted as 1TC-S, 1TC-L and 2TC. A rule-based control algorithm was developed to smoothly switch the STC operation mode using engine speed and load as references. The potential of the STC system in improving the performance of this engine was experimentally examined over a wide range of engine speed and load. When operated at the standard propeller propulsion cycle, the application of the STC system reduced the brake specific fuel consumption (BSFC) by 3.12% averagely. The average of the exhaust temperature before turbine was decreased by 50°C. The soot and oxides of nitrogen (NOx) emissions were reduced respectively. The examination of the engine performance over an entire engine speed and torque range demonstrated the super performance of the STC system in extending the engine operation toward the high torque at low speed (900 to 1200 RPM) while further improving the fuel economy as expected. The engine maximum torque at 900 rpm was increased from 1680Nm to 2361 Nm (40.5%). The average BSFC over entire working area was improved by 7.4%. The BSFC at low load and high torque was significantly decreased. The application of the STC system also decreased the average NOx emissions by 31.5% when examined on the propeller propulsion cycle.

Study on Mixed Pulse Converter (MIXPC) Turbocharging System and Its Application in Marine Diesel Engines

2010 ◽  
Vol 54 (01) ◽  
pp. 68-77
Author(s):  
Yi Cui ◽  
Hongzhong Gu ◽  
Kangyao Deng ◽  
Shiyou Yang
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Thermal Load ◽  
Fuel Efficiency ◽  
Operating Conditions ◽  
Tvd Scheme ◽  
Boost Pressure ◽  
Turbocharging System ◽  
Marine Diesel ◽  
Pulse Converter

In order to improve fuel efficiency and power density, the boost pressure of diesel engine is increasing continuously. The increase in boost level leads to some problems, such as lack of air under part load operating conditions, response delay during transient processes, and high mechanical and thermal load. In order to meet the high boost level demand, a new type of turbocharging system—mixed pulse converter (MIXPC) turbo-charging system for multicylinder diesel engines (from 4 to 20 cylinders) has been invented. A turbocharged diesel engine simulation model, based on one-dimensional finite volume method (FVM) and total variation diminishing (TVD) scheme, has been developed and used to design and analyze the MIXPC turbocharging system. The applications of MIXPC system in in-line 8- and 4-cylinder and V-type 16-cylinder medium-speed marine diesel engines have been studied by calculation and experiments. The results show that the invented MIXPC system has superior engine fuel efficiency and thermal load compared with original turbocharging systems.

scholarly journals ЗАСТОСУВАННЯ МЕТОДУ БЕЗГРАДІЕНТНОЇ ОПТИМІЗАЦІЇ ПРИ СИНХРОНІЗАЦІЇ ДАНИХ МОНІТОРИНГУ РОБОЧОГО ПРОЦЕСУ ДВИГУНІВ ВНУТРІШНЬОГО ЗГОРЯННЯ

2018 ◽  
pp. 9-18
Author(s):  
Роман Анатолійович Варбанець ◽  
Євген Вікторович Белоусов ◽  
Олексій Валерійович Єриганов ◽  
Владислав Іванович Кирнац ◽  
Владислав Олегович Маулевич ◽  
...  
Keyword(s):  
Diesel Engines ◽  
High Efficiency ◽  
Gradient Methods ◽  
Least Square Method ◽  
Least Square ◽  
Data Synchronization ◽  
Maximum Pressure ◽  
Indicator Diagram ◽  
Marine Diesel ◽  
Crankshaft Rotation

The possibility of using the gradientless n-parametric minimization of Powell'64 in the tasks of monitoring the workflow of ship diesel engines is considered. Monitoring the workflow of ship diesel engines includes the problem of cyclical analysis of indicator diagrams in the working cylinders. The problem of data synchronization should be solved - the transfer of pressure charts from the time function to an angle of crankshaft rotation function. It is shown that the hardware detection of the crankshaft rotation phases applying pick-up sensors configured in statics will have errors when the engine is under load. The synchronization task should be solved with the help of an algorithm by analyzing the indicator diagram in real time. Examples of the search for a global minimum of the Rosenbrock test function are given. Applying the Powell'64 method, least square method functionals are minimized in problems of synchronization and modeling of compression-expansion curves in the working cylinder. Cases of data synchronization calculation for low-speed two-stroke and mid-envelope four-stroke marine diesel engines are shown. Taking into account the assumptions made in practice, it was shown that at the point of maximum pressure growth rate on the compression curve, the cylinder volume above the piston can be calculated applying the known geometric dimensions of the cylinder and the P and dP/dφ values obtained from the indicator diagram. The next step is to calculate the first approximation of the position of the top dead center of the piston, and the application of the digital filters is necessary. Finally, the synchronization problem is solved on the basis of the equation dP/dφ = 0, compiled for the section from the start of compression to the start of combustion in the cylinder. The selection of boundary conditions for modeling is shown. The advantage of applying the Powell'64 method is its high efficiency for quadratic functionals. Unlike gradient methods, the Powell'64 method does not require the calculation of derivatives and is universal to minimize complex nonlinear functionals of a general form. The original author's algorithm for data synchronization by analyzing indicator diagrams, which applies the Powell'64 method, is used in the latest versions of the D4.0HT marine diesel engine monitoring systems

Design and Performance Optimization of Off-highway Diesel Engine with Mechanical Fuel Injection Equipment for TIER-IV Emission Norms

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
K. Subramanian ◽  
A. Kandaswamy ◽  
S. Mhahadevan
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Fuel Efficiency ◽  
Air Flow ◽  
Oxidation Catalyst ◽  
Exhaust Gas ◽  
Transient Performance ◽  
Injection Equipment ◽  
And Performance

The two cylinder diesel engines are most demanding product in Indian market for power genset and tractor applications. But major task faced by engine manufacturers all over the world is to upgrade running engine designs with minimum and cost-effective modifications to meet the next level of emission norms. This saves the precious lead time and investments. In addition uncomplicated design has to be sustained as far as possible while improving emissions. Further the basic desires of the end user in off-road market are good response, transient performance, better low end torque, best fuel efficiency and smooth operation of the engine besides best in class reliability. Additional requirements needed to sustain the market with higher power to weight ratio and increased life of the engine. Henceforth turbocharging applications for off-road diesel engines are promising solution for enhancing rated power, low speed torque, transient performance, optimized fuel efficiency and engine downsizing. A trade-off is required to match some incompatible design issues like overall dimensions, cost, emissions control and performance in order to sustain the existing design. Future diesel engine emission standards will restrict vehicle emissions, particularly nitrogen oxides. In the present work, performance improvement for 1.7L, 2 cylinder in-line naturally aspirated diesel engine with mechanical fuel injection pump for off-road application is developed to contain all needs of the market. Design up-gradation of this engine for Tier IV is made with minimal design changes by optimal combinations of fuel injection equipment. This includes proper optimization of performance with improvements in nozzle geometry, change in injector end pressure. But due to the increased fuel flow rates for improving the engine performance as well as emission reduction, there is also a requirement for increased air flow. Henceforth in this study air flow rate is simulated and discussed for selection of turbocharger and intercooler. Further elaborate design and analysis study is also done on cooled exhaust gas recirculation system for exhaust gas cooling efficiency, Diesel Oxidation catalyst, Selective Catalytic Reduction /Lean NOx Trap substrate selection for reduced pressure drop and maximum retention time for exhaust gas to achieve Tier IV norms in turbocharged intercooled two cylinder engine.

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