Investigation of EGR With EGB (Exhaust Gas Bypass) on Low Speed Marine Diesel Engine Performance and Emission Characteristics

Author(s):  
Zhanguang Wang ◽  
Song Zhou ◽  
Yongming Feng ◽  
Yuanqing Zhu

In 2016, the International Maritime Organization (IMO) has enforced stricter nitrogen oxide (NOx) emission standards. Exhaust gas recirculation (EGR) technology is an effective way to achieve IMO Tier III standards for two-stroke marine diesel engines. This paper selected the 6S50ME-C8.2 diesel engine for the study, by making use of GT-POWER simulation software. In this paper, three different types of EGR were built to investigate the effects of EGR on engine performance and NOx emissions. The results show that both the high pressure EGR system and the low pressure EGR system can reduce NOx emissions with the power drop and BSFC risen. While in the high pressure EGR system combined with EGB, more NOx can be reduced with less power drop and BSFC risen. What is more, the running points of the compressor are still in the high efficient area and away the surge margin. Based on the conclusions, the results obtained in this paper can offer reference for the turbocharged diesel engines with EGR system to reduce NOx emissions and improve engine performance.

Author(s):  
Zhanguang Wang ◽  
Song Zhou ◽  
Yongming Feng ◽  
Yuanqing Zhu

In 2016, the International Maritime Organization (IMO) has enforced stricter nitrogen oxide (NOx) emission standards. Exhaust gas recirculation (EGR) technology is an effective way to achieve IMO Tier III standards for two-stroke marine diesel engines. This paper selected the 6S50ME-C8.2 diesel engine for research, by making use of GT-POWER simulation software. In this paper, three different types of EGR systems were built to investigate the effects of EGR on engine performance and NOx emissions. The results show that both the high pressure EGR system and the low pressure EGR system can reduce NOx emissions with the power drop and BSFC risen. While in the high pressure EGR system combined with CB (cylinder bypass) and EGB (exhaust gas bypass), more NOx emissions can be reduced with less power drop and BSFC risen. What is more, the running points of the compressor are still in the efficient areas and away the surge margin. Based on the conclusions, the results obtained in this paper can provide reference for turbocharged diesel engines with EGR systems to reduce NOx emissions and improve engine performance.


Author(s):  
Dimitrios T. Hountalas ◽  
Georgios N. Zovanos ◽  
David Sakellarakis ◽  
Antonios K. Antonopoulos

Diesel engines are almost exclusively used for propulsion of marine vessels. They are also used for power generation either on vessels or power stations because of their superior efficiency, high power concentration, stability and reliability compared to other alternative power systems. However, a significant drawback of these engines is the production of exhaust gases some of which are toxic and thus can be a threat to the environment. The most important toxic gaseous pollutants found in the exhaust gas of a marine diesel engine are NOx (NO, NO2 etc), CO and SOx. Particulate matter is also a major pollutant of diesel. Currently CO2 is considered to be also a “pollutant”, even though not being directly toxic, due to its impact on global warming. In the Marine sector there exists legislation for marine diesel engine NOx emissions which is getting stricter as we move on towards Tier III. This brings new challenges for the engine makers as far as NOx control and its reduction is concerned. Towards this effort of NOx reduction, modelling has an important role which will become even more important in the future. This is mainly attributed to the large size of marine engines which makes the use of experimental techniques extremely expensive and time consuming. Modelling can greatly assist NOx reduction efforts at least at the early stages of development leading to cost reduction. As known NOx emissions are strongly related to engine performance and thus efforts for their reduction usually have a negative impact on efficiency and particulate matter. Modelling can play an important role towards this direction because optimization techniques can be applied to determine the optimum design for NOx reduction with the lowest impact on efficiency. At present an effort is made to apply an existing well validated multi-zone combustion model for DI diesel engines on a 2-stroke marine diesel engine used to power a tanker vessel. The model is used to determine both engine performance and NOx emissions at various operating conditions. To validate model’s ability to predict performance and NOx emissions, a comparison is given against data obtained from the vessel official NOx file and from on board measurements conducted by the present research group. On board performance measurements were conducted using an in-house engine diagnostic system while emissions were recorded using a portable exhaust gas analyzer. From the comparison of measured against predicted data, the ability of the model to adequately predict performance and NOx emissions of the slow speed 2-stroke marine diesel engine examined is demonstrated. Furthermore, from the application are revealed specific problems related to the application of such models on large slow speed two-stroke engines which is significantly important for their further development.


Author(s):  
Alfian Firdiansyah ◽  
Nasrul Ilminnafik ◽  
Agus Triono ◽  
Muh Nurkoyim Kustanto

<p class="02abstracttext"><span lang="IN">A small diesel engine is a machine that has high efficiency but causes a high level of pollution. The most widely used fuel so far is fossil energy which is unrenewable energy. The fruit of the Calophyllum inophyllum plant has great potential to be developed as alternative energy for small diesel engines. In this study, the test fuel used was D100, B100, E5, E10, and E15. The small engine diesel used TG-R180 Diesel with a compression ratio of 20:1 at engine turns 1500, 1800, 2100, and 2400 rpm, and the braking load at a constant prony disc brake is 1,5 kg/cm<sup>2</sup>. The result of the study using E10 fuel can improve engine performance and can reduce the opacity of the exhaust gas. The highest power in the D100 fuel at 2100 rpm is 8,06 PS. The highest thermal efficiency of E10 fuel is 50,29%. The use of Calophyllum inophyllum biodiesel (B100) can reduce exhaust gas opacity in small diesel engines when compared to the use of D100. E10 fuel has the lowest exhaust gas opacity rate of 4,1%.</span></p>


Author(s):  
Hechun Wang ◽  
Xiannan Li ◽  
Yinyan Wang ◽  
Hailin Li

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.


2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Lijiang Wei ◽  
Anmin Wu ◽  
Jie Liu ◽  
Mingliang Zhong ◽  
Xuebai Wang

For the two-stroke marine diesel engine, the action of exhaust valve has a significant impact on scavenging and combustion processes and ultimately affects the engine performances and emissions. In order to reduce nitrogen oxides (NOx) emissions of a two-stroke marine diesel engine, different exhaust valve lifts (EVLs) were achieved by computational fluid dynamics simulation method in this study. The NOx reduction effect and influence mechanism of EVL on a two-stroke marine diesel engine were investigated in detail. The results showed that the in-cylinder residual exhaust gas and the internal exhaust gas recirculation (EGR) rate gradually increased with the decreasing EVL. Although the total mass of charge enclosed in the cylinder did not change much, the composition changed gradually and the maximum internal EGR rate reached 13.17% in this study. The maximum compression pressure and combustion pressure both rose first and then decreased with the decreasing EVL. While the start of combustion and the maximum combustion temperature were basically unaffected by EVL, the indicated power of the engine was also not much impacted when the EVL was changed from increasing 10 mm to decreasing 20 mm. The indicated specific fuel consumption first declined slowly and then rose rapidly as the EVL reduction exceeded 20 mm. NOx emissions decreased monotonously with the decreasing EVL. The reduction of NOx formation rate and the amount of NOx formation mass mainly occurred at the middle and late stages of combustion for the downward moving of residual exhaust gas. NOx emissions were reduced by 12.57% without compromising other engine performances at medium-reduced EVL in this study. However, in order to further reduce NOx emissions at low EVLs, other measures may be needed to make the residual exhaust gas more evenly distributed during the initial stage of combustion.


Author(s):  
Alex Y ◽  
Roji George Roy

Biodiesel has become more attractive recently, because of its environmental benefits and the fact that it is made from renewable resources. Over the past few decades, most of the countries depending on diesel engines for transportation. Some of its valuable advantages like highest thermal efficiency made it very popular. At the same time, the cost of diesel fuel is increasing, due to the depletion of fossil fuels. In this current scenario, we need an alternative fuel instead of diesel fuel. Many of the researchers have successfully placed several works on generating energy from different types of alternative sources including solar and some kind of conversion processes including renewable agricultural products into liquid fuel. One of the biggest challenges for developing countries in relation to energy consumption is to develop and implement technologies that help to improve efficiency of automobile engines, also to reduce the emissions of harmful gases and particulate matters. In order to avoid environmental impacts, emissions are reduced or eliminated by introducing renewable energy resources. The present research chronicles the production and testing of renewable biodiesel fuel derived from virgin coconut oil on a diesel engine, to analyses the engine performance and emission characteristics. In the first phase of work, production of biodiesel fuel from virgin coconut oil using transeterification process with two types of catalysts (homogenous and heterogeneous). The preliminary results shows that, with the addition of homogenous catalyst called Potassium Hydroxide (KOH) with methanol shows much higher activity than that of heterogeneous catalysts, and it shows more similar properties with diesel fuel. The results obtained from the chemical test and physicochemical properties of transesterified biodiesel fuel clearly proves the above-mentioned statement. The chemical tests such as GCMS and FT-IR clearly shows that the biodiesel fuel has sufficient amount of volatile components and functional groups. Then, physicochemical properties include, Fire point, Flashpoint, density, and viscosity were analyzed. Finally, Engine performance and Emission characteristics were analysed to confirm, whether this biodiesel fuel is suitable for diesel engines, without any engine modifications. It was found to be, the transesterified virgin coconut oil biodiesel has similar properties to that of the diesel fuel. From the physiochemical properties and engine performance clearly shows that, coconut oil biodiesel is suitable for diesel engine on blending, at a blending percentage level of 20% with conventional diesel fuel. Since the obtained transesterified biofuel can be used as an alternative fuel for diesel engines. The several journal reports and find outs from experimental investigation clearly depicts that the efficiency of the transesterified biofuel mainly depends upon the amount of catalyst adding and type of catalysts present in the biofuel, whether it is homogenous or heterogeneous catalyst is suitable with methanol. Finally, from the analysis made from biodiesel fuel. Coconut Oil Biodiesel fuel has less emission characteristics than that of the diesel fuels.


Fuel ◽  
2022 ◽  
Vol 309 ◽  
pp. 122226
Author(s):  
Xuyang Tang ◽  
Peng Wang ◽  
Zhongyuan Zhang ◽  
Fengli Zhang ◽  
Lei Shi ◽  
...  

Author(s):  
Y J Qian ◽  
C J Zuo ◽  
J Tan ◽  
H M Xu

This article presents the potential of improving engine performance and pollutant emissions of a ZS195 Diesel engine by exhaust gas recirculation (EGR) and intake hydrogen enrichment. The effect of EGR level and hydrogen addition on the engine performance and pollutant emissions has been investigated through detailed experiments at rated speed. The experimental results have shown that when EGR level is constant, the peak pressure and maximum rate of pressure rise increase with the increase of hydrogen addition. The intake hydrogen enrichment can reduce HC, CO, and soot level and increase NOX emission, but EGR technique can offset this effect. The combustion speed and thermal efficiency increase with the increase of hydrogen addition when EGR technique has been adopted.


2020 ◽  
Vol 8 (10) ◽  
pp. 747
Author(s):  
Vladimir Pelić ◽  
Tomislav Mrakovčić ◽  
Vedran Medica-Viola ◽  
Marko Valčić

The energy efficiency and environmental friendliness of medium-speed marine diesel engines are to be improved through the application of various measures and technologies. Special attention will be paid to the reduction in NOx in order to comply with the conditions of the MARPOL Convention, Annex VI. The reduction in NOx emissions will be achieved by the application of primary and secondary measures. The primary measures relate to the process in the engine, while the secondary measures are based on the reduction in NOx emissions through the after-treatment of exhaust gases. Some primary measures such as exhaust gas recirculation, adding water to the fuel or injecting water into the cylinder give good results in reducing NOx emissions, but generally lead to an increase in fuel consumption. In contrast to the aforementioned methods, the use of an earlier inlet valve closure, referred to in the literature as the Miller process, not only reduces NOx emissions, but also increases the efficiency of the engine in conjunction with appropriate turbochargers. A previously developed numerical model to simulate diesel engine operation is used to analyse the effects of the Miller process on engine performance. Although the numerical model cannot completely replace experimental research, it is an effective tool for verifying the influence of various input parameters on engine performance. In this paper, the effect of an earlier closing of the intake valve and an increase in inlet manifold pressure on fuel consumption, pressure and temperature in the engine cylinder under steady-state conditions is analysed. The results obtained with the numerical model show the justification for using the Miller processes to reduce NOx emissions and fuel consumption.


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