Computational Investigation of In-Cylinder NOX Emissions Reduction in a Large Marine Diesel Engine Using Water Addition Strategies

2010 ◽  
Author(s):  
Christos Chryssakis ◽  
Lambros Kaiktsis ◽  
Athanasios Frangopoulos
Keyword(s):  
Diesel Engine ◽  
Emissions Reduction ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Computational Investigation ◽  
Water Addition ◽  
Marine Diesel

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.

Nitrogen Oxides Reduction Effect and the Influence Mechanism of Exhaust Valve Lift on a Two-Stroke Marine Diesel Engine

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Lijiang Wei ◽  
Anmin Wu ◽  
Jie Liu ◽  
Mingliang Zhong ◽  
Xuebai Wang
Keyword(s):  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Exhaust Valve ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Nox Formation ◽  
Influence Mechanism ◽  
Marine Diesel ◽  
Reduction Effect

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.

A Study on Reducing the NOx Emission of the L21/31 Medium-Speed Marine Diesel Engine for IMO Tier Emission Legislation

2013 ◽  
Vol 291-294 ◽  
pp. 1920-1924
Author(s):  
Min Xiao ◽  
Hui Chen
Keyword(s):  
Numerical Simulation ◽  
Diesel Engine ◽  
Fuel Injection ◽  
Nox Emission ◽  
Injection Timing ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Variable Parameters ◽  
Medium Speed ◽  
Marine Diesel

The KIVA-3V program was used to make numerical simulation for L21/31 type of medium-speed marine diesel engine about the NOx emissions and the affection of NOx changing process on different variable parameters under the Tier Ⅱstandard. On this basis, a discussion towards the NOx emission of the model fueling with dimethyl ether (DME) to meet the Tier Ⅲ standard is offered. The results show that reducing the intake temperature, load and speed, postponing the fuel injection timing and intake lag angle properly can decrease the NOx emissions within the limits of NOx in TierⅡ standard. Comparing the results of the numerical simulation of DME and diesel fuel, the NOx emission of the former one is 60.85% of the latter one, and the NOx emission of changing variable parameters on DME engine is 35.56% of the original type of diesel engine, very close to the Tier Ⅲ.

TEST RESULTS FOR TOXICITY AND REDUCING TOXIC EXHAUST EMISSIONS OF THE MARINE DIESEL ENGINE

2018 ◽  
Author(s):  
Van Ha Pham ◽  
◽  
Ha Hiep Nguyen ◽  
Keyword(s):  
Experimental Investigation ◽  
Diesel Engine ◽  
Diesel Fuel ◽  
Exhaust Emissions ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Test Results ◽  
Test Cycle ◽  
Marine Diesel ◽  
Comparative Experimental Investigation

The tests were carried out on the marine diesel engine operating by the load characteristic in seven modes, including five modes according to the test cycle D2 regulated by ISO 8178. Based on the experimental results obtained, the specific weighted NOx emissions and their average values were calculated and compared with IMO regulations. In addition, the study carried out a comparative experimental investigation on diesel fuel and dimethyl ether, and different injector opening pressures in the marine diesel engine to reduce its toxic exhaust emissions.

Validation of Multi-Zone Combustion Model Ability to Predict Two Stroke Diesel Engine Performance and NOx Emissions Using on Board Measurements

2012 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Georgios N. Zovanos ◽  
David Sakellarakis ◽  
Antonios K. Antonopoulos
Keyword(s):  
Particulate Matter ◽  
Diesel Engine ◽  
Nox Reduction ◽  
Engine Performance ◽  
Combustion Model ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Slow Speed ◽  
Marine Diesel

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.

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