scholarly journals Effect of Early Closing of the Inlet Valve on Fuel Consumption and Temperature in a Medium Speed Marine Diesel Engine Cylinder

2020 ◽  
Vol 8 (10) ◽  
pp. 747
Author(s):  
Vladimir Pelić ◽  
Tomislav Mrakovčić ◽  
Vedran Medica-Viola ◽  
Marko Valčić
Keyword(s):  
Diesel Engine ◽  
Numerical Model ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Nox Emissions ◽  
Inlet Valve ◽  
Engine Operation ◽  
Medium Speed ◽  
Engine Cylinder ◽  
Marine Diesel

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.

scholarly journals Analysis of the Impact of Split Injection on Fuel Consumption and NOx Emissions of Marine Medium-Speed Diesel Engine

2020 ◽  
Vol 8 (10) ◽  
pp. 820
Author(s):  
Vladimir Pelić ◽  
Tomislav Mrakovčić ◽  
Radoslav Radonja ◽  
Marko Valčić
Keyword(s):  
Diesel Engine ◽  
Numerical Model ◽  
Fuel Consumption ◽  
Electric Propulsion ◽  
Nox Emissions ◽  
Split Injection ◽  
Propulsion Systems ◽  
Medium Speed ◽  
The Impact ◽  
Marine Medium

The medium-speed diesel engine in diesel-electric propulsion systems is increasingly used as the propulsion engine for liquefied natural gas (LNG) ships and passenger ships. The main advantage of such systems is high reliability, better maneuverability, greater ability to optimize and significant decreasing of the engine room volume. Marine propulsion systems are required to be as energy efficient as possible and to meet environmental protection standards. This paper analyzes the impact of split injection on fuel consumption and NOx emissions of marine medium-speed diesel engines. For the needs of the research, a zero-dimensional, two-zone numerical model of a diesel engine was developed. Model based on the extended Zeldovich mechanism was applied to predict NOx emissions. The validation of the numerical model was performed by comparing operating parameters of the basic engine with data from engine manufacturers and data from sea trials of a ship with diesel-electric propulsion. The applicability of the numerical model was confirmed by comparing the obtained values for pressure, temperature and fuel consumption. The operation of the engine that drives synchronous generator was simulated under stationary conditions for three operating points and nine injection schemes. The values obtained for fuel consumption and NOx emissions for different fuel injection schemes indicate the possibility of a significant reduction in NOx emissions but with a reduction in efficiency. The results showed that split injection with a smaller amount of pilot fuel injected and a smaller angle between the two injection allow a moderate reduction in NOx emissions without a significant reduction in efficiency. The application of split injection schemes that allow significant reductions in NOx emissions lead to a reduction in engine efficiency.

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).

scholarly journals The influence of fuel injection pump malfunctions of a marine 4-stroke Diesel engine on composition of exhaust gases

2016 ◽  
Vol 167 (4) ◽  
pp. 53-57
Author(s):  
Joanna LEWIŃSKA
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Thermodynamic Parameters ◽  
Laboratory Study ◽  
Fuel Injection ◽  
Marine Diesel Engine ◽  
Fuel Pump ◽  
Engine Cylinder ◽  
Marine Diesel ◽  
Fuel Leakage

The article presents results of a laboratory study on exhaust gas emission level from a marine diesel engine. The object of the laboratory study was a four-stroke marine diesel engine type Al 25/30 Sulzer, operated at a constant speed. The examination on the engine was carried out according to regulations of the Annex VI to MARPOL 73/78 Convention. The laboratory study consisted of 3 observations: the engine assumed to be operating without malfunctions, delay of the fuel injection by 5° of crankshaft angle in the second engine cylinder, and the leakage of the fuel pump on the second engine cylinder. Additionally, parameters of fuel consumption and thermodynamic parameters of the marine engine were measured during the research. Simulated malfunctions caused changes in total weighed NOx, CO, and CO2 emissions for all considered engine loads. All simulated malfunctions caused a small change in measured thermodynamic parameters of the engine. The engine operation with the delayed fuel injection and the fuel leakage in the fuel pump in one cylinder caused a decrease of NOx and CO emission level. Fuel leakage in the fuel pump causes the CO2 emission to decrease only at low engine load. Calculations of the weighed specific fuel consumption present a 1-2% change in the engine efficiency.

Evaluation of Biodiesel Blends in a Single-Cylinder Medium-Speed Diesel Engine

2005 ◽  
Author(s):  
Fan Su ◽  
Malcolm Payne ◽  
Manuel Vazquez ◽  
Peter Eggleton ◽  
Alex Vincent
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Engine Performance ◽  
Injection Pressure ◽  
Frying Oil ◽  
Nox Emissions ◽  
Biodiesel Blends ◽  
Single Cylinder ◽  
Additional Information ◽  
Medium Speed

Biodiesel blends were prepared by mixing low sulphur #2 diesel and biodiesel of two origins (canola and frying oil) at two different concentrations (5% and 20%). They were tested in a single-cylinder four-stroke medium-speed diesel engine under three engine modes representing idle, about 50% power and full load conditions. Engine performance and emissions data obtained with the blends were compared to that of engine running with the #2 diesel. Results indicated that the 5% blends could maintain engine power and fuel economy. Frying oil based B5 provided more significant reductions on CO, THC and PM emissions and increments on NOx emissions as compared with that of the canola B5 fuel. The 20% blends reduce engine CO, PM and smoke emissions, but increase NOx emissions by up to approximately 8%. Engine cylinder pressure and injection pressure data was also collected to provide additional information for evaluation of fuel economy and emissions benefits of using the blends.

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.

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.

Impact of Compressor Surge on Performance and Emissions of a Marine Diesel Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Nikolaos-Alexandros Vrettakos
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Engine Performance ◽  
Marine Diesel Engine ◽  
Performance Parameters ◽  
Test Bed ◽  
Engine Operation ◽  
Compressor Surge ◽  
Marine Diesel ◽  
The Impact

The operation during compressor surge of a medium speed marine diesel engine was examined on a test bed. The compressor of the engine's turbocharger was forced to operate beyond the surge line, by injecting compressed air at the engine intake manifold, downstream of the compressor during steady-state engine operation. While the compressor was surging, detailed measurements of turbocharger and engine performance parameters were conducted. The measurements included the use of constant temperature anemometry for the accurate measurement of air velocity fluctuations at the compressor inlet during the surge cycles. Measurements also covered engine performance parameters such as in-cylinder pressure and the impact of compressor surge on the composition of the exhaust gas emitted from the engine. The measurements describe in detail the response of a marine diesel engine to variations caused by compressor surge. The results show that both turbocharger and engine performance are affected by compressor surge and fast Fourier transform (FFT) analysis proved that they oscillate at the same main frequency. Also, prolonged steady-state operation of the engine with this form of compressor surge led to a non-negligible increase of NOx emissions.

Study on Effect of Electronically Controlled EGR System on Diesel Engine Performance

2011 ◽  
Vol 80-81 ◽  
pp. 1128-1132
Author(s):  
Zhong Gen Su ◽  
Jiang Qi Long
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
High Load ◽  
Significant Decline ◽  
Specific Fuel Consumption ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Electronic Control ◽  
Test Engine

This paper designs an electronic control EGR system used in diesel engine and researches the influence of different EGR rate on engine economy and the emission characteristics of the 13- modes cycle. The results show that the specific fuel consumption of the test engine rises at different degrees after using electronically controlled EGR technology, especially in high load areas; NOx emissions have a more significant decline and particles increase to a certain extent; Overall, however, emissions of HC do not nearly change; CO emissions are closely related to EGR rate.

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

2017 ◽  
Author(s):  
Zhanguang Wang ◽  
Song Zhou ◽  
Yongming Feng ◽  
Yuanqing Zhu
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Engine Performance ◽  
Simulation Software ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Performance And Emission ◽  
High Efficient ◽  
Marine Diesel

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.

Turbocharging a Medium Speed Diesel Engine to Suit Different Applications

2001 ◽  
Author(s):  
Andrei Ludu ◽  
Gernot Athenstaedt ◽  
Stephen G. Dexter
Keyword(s):  
Power Generation ◽  
Diesel Engine ◽  
Engine Speed ◽  
Engine Performance ◽  
Fine Tuning ◽  
Engine Operation ◽  
Application Range ◽  
Drilling Rig ◽  
Marine Propulsion ◽  
Medium Speed

Abstract The turbocharger match plays a key role for a successfully developed engine. Properly matched turbochargers ensure a good gas exchange, the right air flow rates, and air-fuel ratios as required for the combustion fine tuning. AVL LIST GmbH in Graz, Austria, starting from a blank computer display, designed, developed and tested a medium speed diesel engine to cover three applications: power generation, marine propulsion and drilling rig drive. The 12 cylinder vee engine has 2370 HP rated power at 1500 rpm rated engine speed. For the drilling rig drive application 8% torque backup at low engine speed is available. The turbocharging challenge was to specify a turbocharger to suit all three applications. Thus, the turbocharger operation ranged from the constant engine speed operation for power generation, to variable engine speed operation for marine propulsion and with torque backup for the drilling rig drive application. The paper reports test results which demonstrate that AVL could match the engine over a wide application range. The engine performance and system layout calculations performed prior to testing were validated by tests. The engine performance software used is presented. A special emphasis is placed on the implementation, operation and impact of a bypass and waste-gate system as an aid to match the turbocharger for the engine operation with torque back-up.

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