scholarly journals ЗАСТОСУВАННЯ ГАЗОДИНАМІЧНОГО ОХОЛОДЖЕННЯ В СИСТЕМАХ РЕЦИРКУЛЯЦІЇ ВІДХІДНИХ ГАЗІВ СУДНОВИХ ДИЗЕЛІВ

2019 ◽  
pp. 81-86
Author(s):  
Дмитро Вікторович Коновалов
Keyword(s):  
Fuel Consumption ◽  
Exhaust Gas Recirculation ◽  
Back Pressure ◽  
Specific Fuel Consumption ◽  
Design Solution ◽  
Exhaust Gas ◽  
Engine Fuel ◽  
Gas Dynamics Equations ◽  
Exhaust Gases ◽  
Gas Recirculation

There are many ways and methods to reduce exhaust gases emissions on modern ships. One of the most effective ways to reduce NOx and SOx emissions is to use of exhaust gas recirculation (EGR technology). The EGR system disadvantage is an increase in back pressure through additional pressure losses in the scrubber and heat ex-changer, which entails an engine fuel efficiency deterioration. Creating a reliable and efficient heat exchanger for cooling recirculation gases is a complex task due to deposits and pollution emitted by these gases. In the pre-sent work, the jet apparatus effectiveness named aerothermopressor is analyzed in the scheme with exhaust gases recirculation of the ship low-speed two-stroke engine. Aerothermopressor is a two-phase jet for contact disperse cooling, in which by increasing the heat from the gas stream the gas pressure and cooling are increased. The calculation of the characteristics of the engine was carried out, both in nominal, and in operating modes and in all possible range of partial loads. The installation of the aerothermopressor before the scrubber is pro-posed, which allows reducing engine thermal load. Increasing the pressure in the aerothermopressor by 0.2-0.4 ∙ 105 Pa (6-12 %) allows reducing the back pressure in the gas exhaust system and thus reducing the load on the exhaust gas recirculation fan and when the engine load is higher than 75% in the cold zone, the fan is not need-ed, which additionally allows to reduce the specific fuel consumption. The parameters of the exhaust gases that are going to be recirculated and the processes of their gas-dynamic cooling in the aerothermopressor are based on the developed technique and program using the thermodynamic and gas dynamics equations. The proposed scheme-design solution allows at a high environmental friendliness of the existing exhaust gas recirculation sys-tem to provide a certain reduction in specific fuel consumption. It was determined that the engine specific fuel consumption has been decreasing when the aerothermopressor is used to Dge = 2.5-3.0 g/(kW·h) (1.5-1.7%).

scholarly journals Multiobjective Optimisation of a Marine Dual Fuel Engine Equipped with Exhaust Gas Recirculation and Air Bypass Systems

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5021
Author(s):  
Sokratis Stoumpos ◽  
Gerasimos Theotokatos
Keyword(s):  
Fuel Consumption ◽  
Engine Performance ◽  
Exhaust Gas Recirculation ◽  
Specific Fuel Consumption ◽  
Dual Fuel ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Brake Specific Fuel Consumption ◽  
Gas Recirculation ◽  
Optimisation Techniques

Dual fuel engines constitute a viable solution for enhancing the environmental sustainability of the shipping operations. Although these engines comply with the Tier III NOx emissions regulations when operating at the gas mode, additional measures are required to ensure such compliance at the diesel mode. Hence, this study aimed to optimise the settings of a marine four-stroke dual fuel (DF) engine equipped with exhaust gas recirculation (EGR) and air bypass (ABP) systems by employing simulation and optimisation techniques, so that the engine when operating at the diesel mode complies with the ‘Tier III’ requirements. A previous version of the engine thermodynamic model was extended to accommodate the EGR and ABP systems modelling. Subsequently, a combination of optimisation techniques including multiobjective genetic algorithms (MOGA) and design of experiments (DoE) parametric runs was employed to identify both the engine and the EGR/ABP systems settings with the objective to minimise the engine brake specific fuel consumption and reduce the NOx emissions below the Tier III limit. The derived simulation results were employed to analyse the EGR system involved interactions and their effects on the engine performance and emissions trade-offs. A sensitivity analysis was performed to reveal the interactions between considered engine settings and quantify their impact on the engine performance parameters. The derived results indicate that EGR rates up to 35% are required, so that the investigated engine with EGR and ABP systems, when operating at the diesel mode, achieves compliance with the ‘Tier III’ NOx emissions, whereas the associated engine brake specific fuel consumption penalty is up to 8.7%. This study demonstrates that the combination of EGR and ABP systems can constitute a functional solution for achieving compliance with the stringent regulatory requirements and provides a better understating of the underlined phenomena and interactions of the engine subsystems parameters variations for the investigated engine equipped with EGR and ABP systems.

scholarly journals Efek Aditif LPM dan HPM Terhadap Konsumsi Bahan Bakar Spesifik (Brake Specific Fuel Consumption (BSFC)) dan Emisi Jelaga Mesin Diesel Injeksi Langsung Berbahan Bakar Campuran Solar dan Jatropha dengan Cold EGR (Exhaust Gas Recirculation)

REAKTOR ◽  
2017 ◽  
Vol 16 (3) ◽  
pp. 116
Author(s):  
S Syaiful ◽  
S Sobri
Keyword(s):  
Fuel Consumption ◽  
Diesel Engines ◽  
High Purity ◽  
Alternative Fuels ◽  
Exhaust Gas Recirculation ◽  
Specific Fuel Consumption ◽  
Exhaust Gas ◽  
Brake Specific Fuel Consumption ◽  
Soot Emissions ◽  
Gas Recirculation

Diesel engines have been widely used as a mode of public transport and private vehicles because of several advantages compared to gasoline engines including greater power, fuel economy, high reliability and durability of the engine and lower CO emissions. However, diesel engines release more NOx and soot emissions into the atmosphere. This is a serious problem with the strict regulations regarding exhaust emissions. Besides problems of depletion of fossil fuel reserves require various parties to seek alternative fuels derived diesel fuel. Therefore, this work is intended to reduce soot emissions by adding LPM (low purity methanol) or wet methanol and HPM (high purity methanol) into a mixture of jatropha and diesel fuels. From this research, it is also desirable to observe the effect of methanol additive to the specific fuel consumption. Experiment method was conducted to obtain the correlation between the percentage of methanol to a brake specific fuel consumption (BSFC) and soot emissions. Methanol (LPM and HPM) was varied in the range of 5 to 15% by volume. Jatropha is in the range of 10% to 30%. The rate of EGR (exhaust gas recirculation) expressed by OEV (opening EGR valve) was varied at the opening of 0 to 100%. Engine load was varied from 25 to 100% at intervals of 25%. The engine speed was kept constant of 2000 rpm. The results show that the use of fuel mixture increases evenly BSFC of 5.2% and soot emissions of 65%. Keywords: LPM and HPM, BSFC, soot emissions, jatropha, cold EGR and diesel engine  Abstrak Mesin diesel telah banyak digunakan sebagai moda transportasi umum dan kendaraan pribadi oleh karena beberapa kelebihannya dibandingkan dengan mesin bensin diantaranya daya yang lebih besar, hemat bahan bakar, kehandalan dan ketahanan mesin yang tinggi (high realibility and durability), dan emisi CO yang lebih rendah. Akan tetapi mesin diesel melepaskan lebih banyak emisi NOx dan jelaga ke atmosfir. Hal ini menjadi permasalahan serius dengan semakin ketatnya regulasi menyangkut emisi gas buang. Selain itu permasalahan menipisnya cadangan bahan bakar fosil menuntut berbagai pihak untuk mencari bahan bakar alternatif pengganti solar. Oleh karena itu, penelitian ini bermaksud untuk mereduksi emisi jelaga dengan menambahkan LPM (low purity methanol) atau wet methanol dan HPM (high purity methanol)kedalam campuran bahan bakar jatropha dan solar. Dari penelitian ini juga diinginkan untuk mengamati pengaruh aditif metanol terhadap konsumsi bahan bakar spesifik. Metode eksperimen dilakukan untuk mendapatkan keterkaitan antara prosentase metanol terhadap brake specific fuel consumption (BSFC)dan emisi jelaga. Metanol (LPM dan HPM) divariasikan pada rentang 5% sampai 15%. Jatropha adalah pada rentang 10% sampai 30%. Laju EGR (exhaust gas recirculation) yang dinyatakan oleh OEV (opening EGR valve) divariasikan pada bukaan 0% sampai 100%. Beban mesin divariasikan dari 25% sampai 100% dengan interval 25%. Putaran mesin dipertahankan konstan 2000 rpm. Hasil-hasil penelitian menunjukkan bahwa penggunaan bahan bakar campuran rata-rata meningkatkan BSFC 5,2% dan menurunkan emisi jelaga sampai 65%.

scholarly journals Ensuring Requirements for Emissions of Harmful Substances of Diesel Engines

2020 ◽  
Vol 19 (4) ◽  
pp. 305-310
Author(s):  
G. M. Kuharonak ◽  
D. V. Kapskiy ◽  
V. I. Berezun
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Fuel Consumption ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Average Temperature ◽  
Dispersed Particles ◽  
Harmful Substances ◽  
Gas Recirculation ◽  
Emissions Of Harmful Substances

The purpose of this work is to consider the requirements for emissions of harmful substances of diesel engines by selecting design and adjustment parameters that determine the organization of the workflow, and the exhaust gas cleaning system, taking into account the reduction of fuel consumption. Design elements and geometric characteristics of structures for a turbocharged diesel engine of Д-245 series produced by JSC HMC Minsk Motor Plant (4ЧН11/12.5) with a capacity of 90 kW equipped with an electronically controlled battery fuel injection have been developed: exhaust gas recirculation along the high pressure circuit, shape and dimensions of the combustion chamber, the number and angular arrangement of the nozzle openings in a nozzle atomizer, and inlet channels of the cylinder head. Methods for organizing a workflow are proposed that take into account the shape of the indicator diagrams and affect the emissions of nitrogen oxides and dispersed particles differently. Their implementation allows us to determine the boundary ranges of changes in the control parameters of the fuel supply and exhaust gas recirculation systems when determining the area of minimizing the specific effective fuel consumption and the range of studies for the environmental performance of a diesel engine. The paper presents results of the study on the ways to meet  the requirements for emissions of harmful substances, obtained by considering options for the organization of working processes, taking into account the reduction in specific effective fuel consumption, changes in the average temperature of the exhaust gases and diesel equipment. To evaluate these methods, the following indicators have been identified: changes in specific fuel consumption and average temperature of the toxicity cycle relative to the base cycle, the necessary degree of conversion of the purification system for dispersed particles and NOx. Recommendations are given on choosing a diesel engine to meet Stage 4 emission standards for nitrogen oxides and dispersed particles.

Effect of Exhaust Back Pressure on Performance and Emission Characteristics of Diesel Engine Equipped with Diesel Oxidation Catalyst and Exhaust Gas Recirculation

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Sangamesh Bhure
Keyword(s):  
Fuel Consumption ◽  
Exhaust System ◽  
Diesel Oxidation Catalyst ◽  
Back Pressure ◽  
Oxidation Catalyst ◽  
Exhaust Gas ◽  
Performance And Emission ◽  
Diesel Oxidation ◽  
Gas Recirculation ◽  
Exhaust Valves

Currently the emission norms are becoming more stringent, continuous modifications are taking place in existing I.C engines as well as in after treatment devices (ATDs). Exhaust Gas Recirculation (EGR) and Diesel Oxidation Catalyst (DOC) are the mandatory ATDs controlled electronically to optimize engine brake power, fuel consumption and emissions. The conversion efficiency of ATDs mainly depends on exhaust pressure, temperature, flow rate and fluid characteristics of exhaust gas. However, the installation of ATDs increases the exhaust back pressure in the exhaust system. The back pressure of engine also depends on the parameters like engine operating conditions, design of exhaust valves, valve lift time, exhaust gas dynamics and exhaust manifold design etc. In this paper the attempt is made to study the effect of back pressure on performance and emission of diesel engines equipped with EGR and DOC. Here we have not modified the intake and exhaust valves instead, we varied the back pressure of exhaust system using back pressure control valve (BPCV). BPCV is operated manually at three positions, they are 100%, 87.5% and 75% BPCV lifts. The readings are taken in different combinations of BPCV lifts and brake torque at 20, 40, 60, and 80 N-m. The results obtained shows variation of BPCV lift and brake torque effected on performance of engine, DOC and EGR operations as well as fuel consumption. The NOx is reduced by 15%; HC and CO are reduced significantly. However, there is an increase in brake specific fuel consumption (BSFC) and exhaust smoke.

An experimental investigation on performance, emissions, and combustion in a manifold injection for different exhaust gas recirculation flowrates in hydrogen—diesel dual-fuel operations

2008 ◽  
Vol 222 (11) ◽  
pp. 2131-2145 ◽  
Author(s):  
N Saravanan ◽  
G Nagarajan
Keyword(s):  
Experimental Investigation ◽  
Exhaust Gas Recirculation ◽  
Intake Manifold ◽  
Dual Fuel ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Exhaust Gases ◽  
Injection Duration ◽  
Performance And Emissions ◽  
Gas Recirculation

Hydrogen is receiving considerable attention as an alternative fuel to replace the rapidly depleting petroleum-based fuels. Its clean burning characteristics help to meet the stringent emission norms. In this experimental investigation a single-cylinder diesel engine was converted to operate in hydrogen—diesel dual-fuel mode. Hydrogen was injected in the intake manifold and the diesel was injected directly inside the cylinder. The injection timing and the injection duration of hydrogen were optimized on the basis of performance and emissions. Best results were obtained with hydrogen injection at gas exchange top dead centre with an injection duration of 30° crank angle. The flowrate of hydrogen was optimized as 7.5l/min with optimized injection timing and duration. The optimized exhaust gas recirculation (EGR) flowrate was 20 per cent at 75 per cent load. The optimized timings were chosen on the basis of performance, emission, and combustion characteristics. The EGR technique was adopted in the hydrogen—diesel dual-fuel mode by varying the EGR flowrate from 0 per cent to 25 per cent in steps of 5 per cent. The maximum quantity of exhaust gases recycled during the test was 25 per cent (up to 75 per cent load); beyond that unstable combustion was observed with an increase in smoke. The brake thermal efficiency with 20 per cent EGR decreases by 9 per cent compared with diesel. The nitrogen oxide (NO x) emission in hydrogen manifold injection decreases by threefold with 20 per cent EGR operation at full load. The NO x emission tends to reduce drastically with increase in the EGR percentage at all load conditions owing to the increase in heat capacity of the exhaust gases. The smoke decreases by 80 per cent in the dual-fuel operation compared with diesel at 75 per cent load.

The Asymmetric Twin Scroll Turbine for Exhaust Gas Turbochargers

2008 ◽  
Author(s):  
Markus Mu¨ller ◽  
Thomas Streule ◽  
Siegfried Sumser ◽  
Gernot Hertweck ◽  
Arno Nolte ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Pressure Difference ◽  
Flow Parameter ◽  
Exhaust Gas Recirculation ◽  
Flow Path ◽  
Back Pressure ◽  
Exhaust Gas ◽  
Turbine Wheel ◽  
Radial Turbine ◽  
Gas Recirculation

Current turbocharged diesel engines use exhaust gas recirculation (EGR) to effectively meet emission standards. With exhaust gas recirculation it is possible to keep the nitrogen oxide (NOx) emissions to a minimum, largely by lowering the local peak temperatures in the combustion chamber. Exhaust gas transportation from the exhaust side to the air side can be realized in different ways. All have in common that, a drop of pressure from the exhaust to the air is needed. In this paper the high pressure exhaust gas recirculation concept will be discussed, where the exhaust gases are transported from the upstream side of the turbocharger turbine to the downstream side of the charge air cooler. In this concept a negative pressure difference between turbine inlet and engine intake is needed, leading to inefficient gas exchange and, in the end, increasing fuel consumption. In order to keep the overall fuel consumption increase as low as possible, some of the current 6-cylinder Mercedes-Benz truck engines, that have EGR, are equipped with the so-called asymmetric twin scroll turbine to provide the most efficient exhaust gas transportation. In this design concept the negative pressure difference between engine intake and turbine inlet is generated in just one of the two exhaust branches. Thus, whilst some cylinders are operated with a high exhaust gas backpressure, others are operated with a fuel-saving low exhaust gas back-pressure. The different back-pressures in the two exhaust branches are created by designing each flow path of the twin scroll turbine differently. The exhaust branch with the higher back-pressure needs a turbine scroll with a much smaller flow parameter than the exhaust branch with the lower back-pressure. As both flow paths are coupled to the same turbine wheel, the flow parameter is modified using the design parameters of the scrolls. This produces two totally different turbine concepts in one turbine housing. The turbine path with the higher flow parameter has a classical radial turbine reaction value of 0.5. This flow path can thus be optimized for maximum efficiency in comparison with other radial turbines. In contrast, the turbine path with the lower flow parameter combined with the turbine wheel is operated with a reaction value approaching zero. This flow path tends to need an axial turbine with a high flow direction change like an impulse turbine, even if a radial turbine wheel is used. Operating a radial turbine wheel under this boundary condition needs new development steps to improve the turbine with regard to mechanical feasibility and thermodynamic efficiency. This paper describes the principle mechanism of the asymmetric twin scroll turbine. Detailed engine cycle simulations give a brief introduction into the main advantages of asymmetric turbines in combination with exhaust gas recirculation. Hot gas test stand studies show the principle characteristics of this turbine type and the numerical flow simulations give a detailed insight into the flow phenomena in the turbine. The key design values will be discussed and the future outlook indicates the next development steps that will be required.

scholarly journals Issues related to adjustment of a spark ignition engine with exhaust gas recirculation

2004 ◽  
Vol 119 (2) ◽  
pp. 12-22
Author(s):  
Dariusz PIETRAS ◽  
Maciej SOBIESZCZAŃSKI
Keyword(s):  
Engine Performance ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Negative Influence ◽  
Spark Ignition Engine ◽  
Control Algorithms ◽  
Exhaust Gas ◽  
Exhaust Gases ◽  
Vehicle Engine ◽  
Gas Recirculation

The article presents results of a spark ignition engine examination, which has been conducted to establish the influence of exhaust gases recirculation on the engine performance and the toxic content in exhaust gases. The research concentrated on identifying a range of recirculation levels, which enabled to eliminate its negative influence on the engine performance by means of selecting an appropriate angle of advance. Further, the article discusses the engine examination procedures involving different recirculation control algorithms in the ECM chip. Finally, the article presents EURO II and EURO III tests, conducted on a vehicle/engine controlled by the above-mentioned software.

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